Document support for changing source language

Fixes #876
Signed-off-by: Michal Čihař <michal@cihar.com>

docs/admin/projects.rst

@@ -115,10 +115,13 @@ Enable ACL
     Enable per project access control, see :ref:`acl` for more details.
 Enable hooks
     Whether unauthenticated :ref:`hooks` will be enabled for this repository.
-Owner
-    You can also configure project owner, who will always get important
+Owners
+    You can also configure project owners, who will always get important
     notifications about project and will have additional privileges to control
     translations within this project (see :ref:`privileges`).
+Source language
+    Language used for source strings in all components. Change this if you are 
+    translating from something else than English.
 
 Adjusting interaction
 +++++++++++++++++++++

docs/changes.rst

@@ -21,6 +21,7 @@ Released on ? 2015.
 * Improved support for translating PHP files.
 * Performance improvements for quality checks.
 * Fixed sitewide search for failing checks.
+* Added option to specify source language.
 
 weblate 2.4
 -----------