Adding support for CHEATPATH variable and multiple cheat locations
Added nmap support
Changed from 2-spaces per indentation level to 4, per PEP-8 standard.
Added '-help' and 'cheat' to the list of cheat usage arguments.
Merging gbremer's work into master.
Continuing to merge gbremer's work into master.
Merging shanahanjrs work into master.
Updated the README.
Updated the README to document the usage of the $CHEATPATH environment variable.
More changes to the README.
Fixing a minor typo in the REAMDE.
Merge https://github.com/chrisallenlane/cheat

Conflicts:
	README.md
	cheat
	install
Remove duplicates from the list of cheatsheets.