Application-wide constants moved to separate module.
Merge branch 'master' of https://github.com/volks73/descatter.git

Conflicts:
	descatter/constants.py
Added greater functionality to the console interface and tested it. The
console now keeps a history of all used directives that can be called on
by name, using the '-n' argument of the 'file' command, instead of
typing out the file path every time. The most recent directive is also
saved, so the '-n' and '-d' arguments are not needed every time for the
'file' command. A simple directive to copy a file from the source to a
destination was also created. The simple directive mimics a copy and
paste system command.