Adds a git alias for GNU-like word diff output.
Adds bash aliases to list top level node packages.
Adds markdown file type for ack searches.

The option --sort-files was not recognized so it has been commented out.
Adds descriptions from the ack documentation for all option set.
Adds GPG2 to Brewfile list of Homebrew packages.

Removes Netlogo and OmniGraffle from the Homenbrew Casksfile list.
OmniGraffle should now be installed through the Mac App Store.