Merge pull request #99 from hwhw/ffi-framebuffer-native

Framebuffer features/fixes for Kobo
Handle Kobo backlight via FFI instead of Lua/C API
fix reflow-to-native position transform
This patch depends on koreader/libk2pdfopt#17.
fix compilation complains of GCC 4.8.1 on Ubuntu Saucy
Merge pull request #102 from chrox/master

fix reflow-to-native position transform
update k2pdfopt to version 2.12
add Travis CI config file
Merge pull request #103 from chrox/master

update k2pdfopt to version 2.12
add travis-ci status in README
make test in .travis.yml
Merge pull request #104 from chrox/master

make test in .travis.yml
Merge pull request #101 from hwhw/kobolight-ffi

Handle Kobo backlight via FFI instead of Lua/C API
adaption of Lua/C-API for ffi KOPTContext
add ffi KOPTContext module
install tesseract data in travis
fix type of ocr_type variable in libk2pdfopt
add missing test PDF file
install tessdata into right place
Update .travis.yml
export TESSDATA_PREFIX env in travis