Add a Setup project that creates an installer.

The Setup project has been configured to build only in Release mode.
In addition to everything else, the installer currently copies a single test level
  to the user's AppData/Local folder. This level is not used, but it is a proof of
  concept of how to store the levels in a user-accessible area.
The AppData/Local folder is also where user progress and preferences should be saved.
Fix some silly mistakes, like not marking the XNA redistributable as a requirement.
Minor changes.
Merge branch 'create-installer'