Use process cwd instead of assembly reference
Put remove routines into seperate methods

Replaced duplicate iterations with recursion
Use SearchOption.AllDirectories to find all files instead of recursion
Removed the obligatory '-ok' argument. If omitted, we go safe mode.
Misc. changes

 - Changed target framework to .NET 3.5 Client
 - Formatting variables and code layout
 - Added exit code 2 to happen if files failed to remove
 - A more kickass README.