Merge pull request #181 from chrox/master

handle key and cmd events on Android
refactor(pic): finsih ffi binding
feature(blitbuffer): add scale method

scale method allocates a new blitbuffer with scaled width and height
feature(blitbuffer): add isEqual method
test(blitbuffer): style cleanup & add scale and isEqual tests.
Merge pull request #182 from houqp/pic

finish ffi binding for pic module
clean(build): remove libkoreader-pic module
Merge pull request #183 from houqp/houqp-master

clean(build): remove libkoreader-pic module