Update providers.xml

about 70% of russian mailboxes. it works
Replace synchronous setting of a flag with async setting of the flag. This helps speed up message display time (anecdotally)
Marking a message as read in the database is currently very expensive, especially if you have threading enabled.

Defer that until _after_ telling listeners that they're cool to show the message
Opening a folder (especially in threaded mode) does a very heavy SQL query. This method doesn't use or modify the folder object.  Don't cargo-cult the Open here.

(cketti may well tell me I'm wrong about this. Happy to listen & fix)
4.506 changelog
Bumped manifest to 4.506
SK translation - fixes
Sk fixes
Update providers.xml

updated
Updated Japanese translation of the changelog.
Merge pull request #330 from bboa/master

Added Russian mail providers
Add Russian ISPs -> changelog
Another fix
Updated/fixed polish translation.
Polish translation updated - remote search left.
Polish translation - quick fixes.
Updated polish translation - quick fixes, credits update.
Merge pull request #337 from sq5gvm/master

Update polish translation
Merge pull request #332 from pylerSM/patch-1

Fix Slovak translation
Update gradle version as required for Android Studio 0.2.x