Use `int` for all message buffer ops

[joe0x04]

The current buffer reading funcs will return numbers of the same size that were read. Shorts return a 16 bit number, int/long returns 32 bit numbers etc. This results in needing to use casting funcs all over the place. Change these functions to return standard ints and handle the length internally.

[joe0x04]

This will most likely have ramifications for a large number of other projects. Doing this work in the intbuffers branch