[enh] i18n support

searx/engines/__init__.py

 from searx.utils import gen_useragent
 import sys
 from datetime import datetime
+from flask.ext.babel import gettext
 
 engine_dir = dirname(realpath(__file__))
 
             engine['percentage'] = 0
 
     return [
-        ('Page loads (sec)', sorted(pageloads, key=itemgetter('avg'))),
         (
-            'Number of results',
+            gettext('Page loads (sec)'),
+            sorted(pageloads, key=itemgetter('avg'))
+        ),
+        (
+            gettext('Number of results'),
             sorted(results, key=itemgetter('avg'), reverse=True)
         ),
-        ('Scores', sorted(scores, key=itemgetter('avg'), reverse=True)),
         (
-            'Scores per result',
+            gettext('Scores'),
+            sorted(scores, key=itemgetter('avg'), reverse=True)
+        ),
+        (
+            gettext('Scores per result'),
             sorted(scores_per_result, key=itemgetter('avg'), reverse=True)
         ),
-        ('Errors', sorted(errors, key=itemgetter('avg'), reverse=True)),
+        (
+            gettext('Errors'),
+            sorted(errors, key=itemgetter('avg'), reverse=True)
+        ),
     ]

searx/templates/engines.html

 {% extends 'base.html' %}
 {% block content %}
 <div class="row">
-<h2>Currently used search engines</h2>
+    <h2>{{ _('Currently used search engines') }}</h2>
 
     <table style="width: 80%;">
         <tr>
-            <th>Engine name</th>
-            <th>Category</th>
+            <th>{{ _('Engine name') }}</th>
+            <th>{{ _('Category') }}</th>
         </tr>
     {% for (categ,search_engines) in categs %}
         {% for search_engine in search_engines %}
         {% endfor %}
     {% endfor %}
     </table>
-<p>Please add more engines to this list, pull requests are welcome!</p>
-<p class="right"><a href="/">back</a></p>
+<p class="right"><a href="/">{{ _('back') }}</a></p>
 </div>
 {% endblock %}

searx/templates/index.html

     <div class="title"><h1>searx</h1></div>
     {% include 'search.html' %}
     <p class="top_margin">
-        <a href="/about" class="hmarg">about</a>
-        <a href="/preferences" class="hmarg">preferences</a>
+        <a href="/about" class="hmarg">{{ _('about') }}</a>
+        <a href="/preferences" class="hmarg">{{ _('preferences') }}</a>
     </p>
 </div>
 {% endblock %}

searx/templates/preferences.html

 {% block head %} {% endblock %}
 {% block content %}
 <div class="row">
-    <h2>Preferences</h2>
+    <h2>{{ _('Preferences') }}</h2>
 
 
     <fieldset>
-        <legend>Default categories</legend>
+        <legend>{{ _('Default categories') }}</legend>
         <form method="post" action="/preferences" id="search_form">
         <p>
         {% include 'categories.html' %}
         </p>
-        <input type="submit" value="save" />
+        <input type="submit" value="{{ _('save') }}" />
         </form>
     </fieldset>
-    <div class="right"><a href="/">back</a></div>
+    <div class="right"><a href="/">{{ _('back') }}</a></div>
 </div>
 {% endblock %}

searx/templates/results.html

 </div>
 <div id="results">
     {% if suggestions %}
-    <div id="suggestions"><span>Suggestions: </span>{% for suggestion in suggestions %}<form method="post" action="/"><input type="hidden" name="q" value="{{suggestion}}"><input type="submit" value="{{ suggestion }}" /></form>{% endfor %}</div>
+    <div id="suggestions"><span>{{ _('Suggestions') }}:</span>{% for suggestion in suggestions %}<form method="post" action="/"><input type="hidden" name="q" value="{{suggestion}}"><input type="submit" value="{{ suggestion }}" /></form>{% endfor %}</div>
     {% endif %}
 
 
     <div id ="result_count">
-        Number of results: {{ number_of_results }}
+        {{ _('Number of results') }}: {{ number_of_results }}
     </div>
 
     {% for result in results %}
         {% endif %}
     {% endfor %}
     <div id="apis">
-      Download results
+      {{ _('Download results') }}
       <form method="post" action="/">
         <div class="left">
           <input type="hidden" name="q" value="{{ q }}" />

searx/templates/stats.html

 {% extends "base.html" %}
 {% block head %} {% endblock %}
 {% block content %}
-<h2>Engine stats</h2>
+<h2>{{ _('Engine stats') }}</h2>
 
 {% for stat_name,stat_category in stats %}
 <div class="left">