Micro-optimize innermost processing loop in compress().
Micro-optimize innermost processing loop in compress().

This lifts the close-to-end-of-buffer check out of the loop, for performance.

Inlining the entire if/else expression rather that introducing another local variable is also a (small) win.

unwind/python-lzjb,unwind/python-lzjb,unwind/python-lzjb