1. Added new global function in our global functions file "removeDebianPackage".
2. Updated all role scripts to use the common function code instead of their own individual functions.
Updated such that role scripts all live in one directory, regardless of
the distribution to which they are meant to be applied.
This role directory can be specified with "--roledir", or via the configuration file setting "roledir=/path/to/dir".
See the following bug for rationale:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=383822