Fix indents & organize imports (res & src)
Return an empty list if there is no data and no error

Fixes #195
Merge pull request #194 from ratan12/Fix_indentations

Fix indents & organize imports (res & src)
Merge pull request #196 from d-sko/networktask_fix

Don't return null for list tasks with empty results in NetworkTask
Switch to Account manager, syncadapter & contentprovider.

Changes in short:
- Cleanup unused imports
- Rewritten auto-sync (Works now on the background)
- Prefs user/password has been moved to the safe account manager
- Updated androidmanifest for the requied permissions
- Added/Removed strings
- Removed old settings
- Updated login screen (use accountmanager)