bitmap.py: Rewrite for better clarity and to properly support img files

* Output file may now *optionally* be a .h or .img
* Added sanity check for when input == output
* Possibly fixed error in dataSize field of comressed output files: Previous value of dataSize was 2x reality
bitmap.py: Remove unused variable
bitmap.py: Clarify dataSize and compressedSize as words
Regenerate *.img with new bitmap.py

for f in [0-9]*.h; do ./bitmap.py -i ${f} -o ${f%%.h}.img -n ${f%%.h} -c; done
./bundle.py [0-9]*.img -o bundle.img
Merge branch 'new_bitmap.py'