DRun

Initial git commit. A basic application launcher written in Python with
dmenu.
Rename drun.py for next commit

The next commit will introduce a Makefile that modifies drun.py before
installing it.

This commit exists to make the output of git diff clearer. It does not
change the contents of any file!
Build with Makefile

Building (and installing) with a Makefile is more flexible and makes it
possible for the example configuration to live in its own file.
Support stacking menus

Multiple menus can be displayed by storing them on a stack. The menu on top
of the stack is current.

Pushing a menu onto the stack and calling get_cmd causes it to become the
current menu. At the moment removing the current menu requires the user to
explicitly close it by pressing ESC.
Rename drun.py.in for next commit

The next commit will change the Makefile to install drun.py directly
without modifying it.

This commit exists to make the output of git diff clearer. It does not
change the contents of any file!
Find prefix at runtime

Finding the prefix under which the program is installed at runtime means
that it can be relocated (along with any other installed files) without
breaking.