Merge pull request #1136 from hwhw/master

fix refresh with rotation and viewport
Minor English improvements.
Capitalization: change a few mentions of calibre to lowercase

The author likes it that way. See http://calibre-ebook.com/about
Correct "cannot connect to calibre server string"
Merge pull request #1141 from Frenzie/master

Minor English improvements.
fix cache implementation

the cache would behave badly when the same item was insert()ed twice:
it would add the size twice to memory consumption, but would never substract
it twice when purging the (actually single) object from cache. So the cache
would seem to fill up while in fact it wasn't.
update base

Blitbuffer RGB16 fixes
(should only apply to screenshots for now)