* Fix GCC signed-unsigned and pointer-warnings
A lot of the signed/unsigned issues are related to the fact that I converted
a lot of indexing values to use unsigned types, little did I know that a lot of
other values used when indexing actually come from the python-end. Python does
not have built-in unsigned types so all integers coming from Python are signed
implicitly so a lot of things like image-size and x, y coordiantes are specially
handling negative-integer cases.
Guess we'll just take our `int32_t i = 0; i < blah; ++i` and like it.
Code now compiles with no warnings or nagging.
