Fixed references to doc/HACKING

This patch replaces all references to `doc/HACKING` with `doc/HACKING.md`, to
include the one in `setup.py` that was preventing a successful build. Some
trailing whitespace was incidentally removed.
Fixed references to doc/HACKING (for real)
Merge branch 'fix-hacking-references' of https://github.com/threeifbywhiskey/ranger
update email address
HACKING.md: better specification of python versions
doc: match the default configuration for untag map

Reported-By: Branislav Blaškovič <bblaskov@redhat.com>
Merge branch 'doc-typo' of https://github.com/mathstuf/ranger
rebuilt man page