make functions in MD5 implementation local

also get rid of mostly unused helper libraries and some stylistic
oddities in the MD5 code
calculate proper refresh coordinates when using viewport

The viewport offset used by refresh() was not properly adapted when
the screen was rotated.
add test for md5 implementation
Merge pull request #1129 from hwhw/master

Fixes for Refresh+Viewport, cleanup of MD5 functions
Simplify the H2O special-casing

re #1119

AUTO appears to be doing the right thing...
(even if that baffles me, given the state of the Kernel sources,
unless they flip some switches at compile time
[NTX_WFM_MODE_OPTIMIZED_REAGL / NO_AUTO_REAGL_MODE] ...)

Anyway, that's what nickel does, so follow its lead ;).
Merge pull request #1130 from NiLuJe/master

Simplify the H2O special-casing
Fix refresh in rotated (landscape) mode when using viewport

Rotation wasn't applied to the underlying framebuffer's blitbuffer,
so refresh coordinates were cut off the wrong way.
Merge pull request #1131 from hwhw/master

Fix refresh in rotated (landscape) mode when using viewport
make fake_events device a private feature of the Kindle device initialization

This is highly Kindle-specific, so we keep it there for now
fixes for picdocument

picdocument didn't use the document API correctly
update base

depends on pic_jpeg FFI conversion
Merge pull request #1134 from hwhw/master

Slight refactoring of input, fix picdocument, FFI-API for pic_jpeg
schedule in menu option callback
so that new reginal update on menu entry don't
affect screen update from callback results
Merge pull request #1135 from chrox/fix_touchmenu

schedule in menu option callback