bugfix: typo for Color16:getColor16()
remove wrong assertion

assertion was wrong, but it worked how it was on a Kindle Paperwhite.
So we assume that values from the framebuffer make no sense anyway
and comment out the assertion for now.
fixes in device/framebuffer recognition

we assume that 16bpp framebuffers are Kobo devices
Make mxcfb.h headers for Kindle and Kobo strictly seperate

FFI can include the relevant definitions on the fly
adapt to separated mxcfb.h and einkfb.h headers
Merge pull request #97 from hwhw/ffi-framebuffer-native

fixes for 16bpp framebuffers (Kobo)