Clean up the architecture

Purposes :
- isolate the plugins calls
- distinction between parsing the web request and running the search (Search class). To be able to test code easily, to run searx code outside a web server, to filter the search query parameters with plugins more easily, etc...

Details :
- request.request_data contains request.form or request.args (initialize inside pre_request() function)
- Query class is renamed RawTextQuery
- SearchQuery class defines all search parameters
- get_search_query_from_webapp create a SearchQuery instance (basically the previous Search.__init__ code)
- Search class and SearchWithPlugins class takes a SearchQuery instance as class constructor parameter
- SearchWithPlugins class inherites from Search class, and run plugins
- A dedicated function search_with_plugins executes plugins to have a well define locals() (which is used by the plugins code).
- All plugins code is executed inside the try...except block (webapp.py, index function)
- advanced_search HTTP parameter value stays in webapp.py (it is only part of UI)
- multiple calls to result_container.get_ordered_results() doesn't compute the order multiple time (note : this method was call only once before)
- paging value is stored in the result_container class (compute in the extend method)
- test about engine.suspend_end_time is done during search method call (instead of __init__)
- check that the format parameter value is one of these : html, rss, json, rss (before the html value was assumed but some text formatting wasn't not done)

searx/results.py

@@ -128,6 +128,8 @@ class ResultContainer(object):
         self.suggestions = set()
         self.answers = set()
         self._number_of_results = []
+        self._ordered = False
+        self.paging = False
 
     def extend(self, engine_name, results):
         for result in list(results):
@@ -153,6 +155,9 @@ class ResultContainer(object):
 
         self.results[engine_name].extend(results)
 
+        if not self.paging and engines[engine_name].paging:
+            self.paging = True
+
         for i, result in enumerate(results):
             try:
                 result['url'] = result['url'].decode('utf-8')
@@ -219,7 +224,7 @@ class ResultContainer(object):
             with RLock():
                 self._merged_results.append(result)
 
-    def get_ordered_results(self):
+    def order_results(self):
         for result in self._merged_results:
             score = result_score(result)
             result['score'] = score
@@ -269,8 +274,14 @@ class ResultContainer(object):
                 # update categoryIndex
                 categoryPositions[category] = {'index': len(gresults), 'count': 8}
 
-        # return gresults
-        return gresults
+        # update _merged_results
+        self._ordered = True
+        self._merged_results = gresults
+
+    def get_ordered_results(self):
+        if not self._ordered:
+            self.order_results()
+        return self._merged_results
 
     def results_length(self):
         return len(self._merged_results)