diffhelpers: be more tolerant for stripped empty lines of CRLF ending Exchange. It appears to trim lines containing only whitespace as well as converting LF to CRLF.

diffhelpers: make return value of testhunk() more Pythonic It's no longer C.

patch: error out if reached to EOF while reading hunk This was where out-of-bounds read occurred in old C extension.

diffhelpers: remove unused return value from fixnewline() and addlines()

diffhelpers: move out of pure package

diffhelpers: naming and whitespace cleanup