Update the documentation for binascii and zlib crc32/adler32 functions
to better describe the signed vs unsigned return value behavior on
different platforms and versions of python.  Mention the workaround to
make them all return the same thing by using & 0xffffffff.

Fixes issue4903.

Also needs to be merged into release26-maint, release30-maint, & py3k.
2 files changed