Merge pull request #364 from NiLuJe/master

Possibly slightly less broken PW2 detection
fix kindle paperwhite2 support
reported at http://www.mobileread.com/forums/showpost.php?p=2696481&postcount=316
tested at http://www.hi-pda.com/forum/redirect.php?goto=findpost&ptid=1078988&pid=23393929
revert main GUI font to better-looking DroidSans
Merge pull request #368 from chrox/master

fix kindle paperwhite2 support
remove redundancy: new framebuffer supports rotation, multi-bpp

We can get rid of shadow blitbuffers. Screen.bb is now fb.bb.
All bpp conversion is now done by the blitbuffer abstraction layer.
Rotation mechanism is adapted to this.
replace Screen.width/Screen.height with accessor methods

Screen.width and Screen.height are now gone, use the methods
getWidth() and getHeight() to get the relevant data. They will
take blitbuffer/framebuffer rotation into account.
Merge remote-tracking branch 'upstream/master' into native-framebuffer
update koreader-base

This will need https://github.com/koreader/koreader-base/pull/96 to be applied first
Merge pull request #370 from hwhw/native-framebuffer

FFI framebuffer implementation adaptions
incorporate some fixes to koreader-base
pull Kobo fixes from koreader-base
Merge pull request #371 from hwhw/native-framebuffer

incorporate some fixes to koreader-base
fix default full refresh in Kindle since the new ffi framebuffer
Merge pull request #373 from chrox/master

fix default full refresh in Kindle since the new ffi framebuffer
fix for Kobo framebuffers: allow for rotation at framebuffer setup

the Kobo framebuffer comes up in landscape mode, that is, landscape
in the other direction as we do it when going into landscape mode.
we leave it this way, and rather allow for a rotation correction at
framebuffer setup.

this PR pulls the relevant changes from koreader-base and makes the
screen code aware of this additional rotation setting.

Kobo framebuffers should now work properly with the new framebuffer
FFI code. They can stay in 16bpp mode and don't change the current
framebuffer settings. They should thus properly interoperate with
the native framework on Kobos as well as sergeys KoboLauncher
(no garbled screen when returning)
Merge pull request #374 from hwhw/native-framebuffer

fix for Kobo framebuffers: allow for rotation at framebuffer setup
remove auto "contentwidth" in landscape
This should fix #365.
update pot file
update po file from transifex automatically on each build
force download po files