feat($http): new $http service, removing $xhr.*

Features:
- aborting requests
- more flexible callbacks (per status code)
- custom request headers (per request)
- access to response headers
- custom transform functions (both request, response)
- caching
- shortcut methods (get, head, post, put, delete, patch, jsonp)
- exposing pendingCount()
- setting timeout
Breaks renaming $xhr to $http
Breaks Takes one parameter now - configuration object
Breaks $xhr.cache removed - use configuration cache: true instead
Breaks $xhr.error, $xhr.bulk removed
Breaks Callback functions accepts parameters: response, status, headers
Closes angular#38
Closes angular#80
Closes angular#180
Closes angular#299
Closes angular#342
Closes angular#395
Closes angular#413
Closes angular#414
Closes angular#507

angularFiles.js

@@ -26,10 +26,7 @@ angularFiles = {
     'src/service/routeParams.js',
     'src/service/sniffer.js',
     'src/service/window.js',
-    'src/service/xhr.bulk.js',
-    'src/service/xhr.cache.js',
-    'src/service/xhr.error.js',
-    'src/service/xhr.js',
+    'src/service/http.js',
     'src/service/locale.js',
     'src/directives.js',
     'src/markups.js',