[fix] travis build : various fix about grunt builds

.travis.yml

   - "sh -e /etc/init.d/xvfb start"
   - npm install less less-plugin-clean-css grunt-cli
   - export PATH=`pwd`/node_modules/.bin:$PATH
-  - ls -l $VIRTUAL_ENV
-  - ls -l $VIRTUAL_ENV/bin
-  - ( cd searx/static/themes/oscar;npm install; cd - )
-  - ( cd searx/static/themes/simple;npm install; cd - )
+  - ./manage.sh grunt_packages
   - mkdir -p ~/drivers; export PATH=~/drivers:$PATH;
   - GECKODRIVER_URL="https://github.com/mozilla/geckodriver/releases/download/v0.18.0/geckodriver-v0.18.0-linux64.tar.gz";
   - FILE=`mktemp`; wget "$GECKODRIVER_URL" -qO $FILE && tar xz -C ~/drivers -f $FILE geckodriver; rm $FILE; chmod 777 ~/drivers/geckodriver;

manage.sh

 SEARX_DIR="$BASE_DIR/searx"
 ACTION=$1
 
+cd $BASE_DIR
+
 update_packages() {
     pip install -r "$BASE_DIR/requirements.txt"
 }
     pip install -r "$BASE_DIR/requirements-dev.txt"
 }
 
-check_geckodriver() {
+install_geckodriver() {
     echo '[!] Checking geckodriver'
     set -e
     geckodriver -V 2>1 > /dev/null || NOTFOUND=1
     set -e
     pep8_check
     unit_tests
-    check_geckodriver
+    install_geckodriver
     robot_tests
     set +e
 }
 
 build_style() {
-    # lessc -x "$BASE_DIR/searx/static/$1" "$BASE_DIR/searx/static/$2"
     lessc --clean-css="--s1 --advanced --compatibility=ie9" "$BASE_DIR/searx/static/$1" "$BASE_DIR/searx/static/$2"
 }
 
 styles() {
     echo '[!] Building styles'
-	build_style themes/legacy/less/style.less themes/legacy/css/style.css
-	build_style themes/legacy/less/style-rtl.less themes/legacy/css/style-rtl.css
-	build_style themes/courgette/less/style.less themes/courgette/css/style.css
-	build_style themes/courgette/less/style-rtl.less themes/courgette/css/style-rtl.css
-	build_style less/bootstrap/bootstrap.less css/bootstrap.min.css
-	build_style themes/oscar/less/pointhi/oscar.less themes/oscar/css/pointhi.min.css
-	build_style themes/oscar/less/logicodev/oscar.less themes/oscar/css/logicodev.min.css
-	build_style themes/pix-art/less/style.less themes/pix-art/css/style.css
-	build_style themes/simple/less/style.less themes/simple/css/searx.min.css
-	build_style themes/simple/less/style-rtl.less themes/simple/css/searx-rtl.min.css
+    build_style themes/legacy/less/style.less themes/legacy/css/style.css
+    build_style themes/legacy/less/style-rtl.less themes/legacy/css/style-rtl.css
+    build_style themes/courgette/less/style.less themes/courgette/css/style.css
+    build_style themes/courgette/less/style-rtl.less themes/courgette/css/style-rtl.css
+    build_style less/bootstrap/bootstrap.less css/bootstrap.min.css
+    build_style themes/oscar/less/pointhi/oscar.less themes/oscar/css/pointhi.min.css
+    build_style themes/oscar/less/logicodev/oscar.less themes/oscar/css/logicodev.min.css
+    build_style themes/pix-art/less/style.less themes/pix-art/css/style.css
+    build_style themes/simple/less/style.less themes/simple/css/searx.min.css
+    build_style themes/simple/less/style-rtl.less themes/simple/css/searx-rtl.min.css
+}
+
+grunt_packages() {
+    echo '[!] Grunt packages: install dependencies'
+    cd $BASE_DIR/searx/static/themes/oscar
+    npm install
+    
+    cd $BASE_DIR/searx/static/themes/simple
+    npm install
 }
 
 grunt_build() {
-	grunt --gruntfile "$SEARX_DIR/static/themes/oscar/gruntfile.js"
-	grunt --gruntfile "$SEARX_DIR/static/themes/simple/gruntfile.js"
+    echo '[!] Grunt build : oscar theme'
+    grunt --gruntfile "$SEARX_DIR/static/themes/oscar/gruntfile.js"
+    echo '[!] Grunt build : simple theme'    
+    grunt --gruntfile "$SEARX_DIR/static/themes/simple/gruntfile.js"
 }
 
 locales() {
-	pybabel compile -d "$SEARX_DIR/translations"
+    pybabel compile -d "$SEARX_DIR/translations"
 }
 
 help() {
 
 Commands
 ========
+    grunt_packages       - Download & install dependencies
     grunt_build          - Build js files
     help                 - This text
     locales              - Compile locales
     unit_tests           - Run unit tests
     update_dev_packages  - Check & update development and production dependency changes
     update_packages      - Check & update dependency changes
-    check_geckodriver    - Check & download geckodriver (required for robot_tests)
+    install_geckodriver  - Download & install geckodriver if not already installed (required for robot_tests)
 "
 }
 

searx/static/themes/oscar/gruntfile.js

     jshint: {
       files: ['gruntfile.js', 'js/searx_src/*.js'],
       options: {
+        reporterOutput: "",	    
         // options here to override JSHint defaults
         globals: {
           jQuery: true,
             files: {"css/pointhi.min.css": "less/pointhi/oscar.less",
                     "css/logicodev.min.css": "less/logicodev/oscar.less"}
         },
+        /*
+	// built with ./manage.sh styles
         bootstrap: {
             options: {
                 paths: ["less/bootstrap"],
             },
             files: {"css/bootstrap.min.css": "less/bootstrap/bootstrap.less"}
         },
+        */
     },
     watch: {
         scripts: {

searx/static/themes/simple/gruntfile.js

     jshint: {
       files: ['js/searx_src/*.js'],
       options: {
+        reporterOutput: "",
         proto: true,
         // options here to override JSHint defaults
         globals: {