#18 Get rid of some Python 2.5 warnings in Bitmap.py

[alex_sf]

Lines 203, 205, 207, and 209 (if memory serves) can cause Python 2.5 to fuss.

Replace some of the code with this code that calls int() on the values.

data += pack("<H", int(OT))
data += pack("<H", int(id))
data += pack("<H", int(grbit))
data += pack("<H", int(colL))
data += pack("<H", int(dxL))
data += pack("<H", int(rwT))
data += pack("<H", int(dyT))
data += pack("<H", int(colR))
data += pack("<H", int(dxR))
data += pack("<H", int(rwB))
data += pack("<H", int(dyB))