add sha1.py; still debugging.
Successfully debug sha1; removed excess code.

Identify broken bits of code: round 1 of main for-loop was missing a
binary not, and the for-loop that partitioned 512b blocks into 16 32b
words was defunct. Removed excess code, which was preserved hitherto as
a safety net (for instance, to ensure that re-aliasing didn't go awry
and cause bugs, etc.).
Make minor revisions of c_uint usage.
Implement final changes; add comments

Add comments to several portions to clarify process,
and added output verification.
Ignore.