Added an icon and added a directory for the admin account on Windows

|INSTALLER|
* Added an icon (it's not clear whether this is for the Alt+Tab interface, as
  it has not been tried on a DE with such abilities)
* Added a directory for the administrator account on Windows to install
* (should be <WINDRIVE>:/Program Files on 32-bit native and 64-bit, and
  <WINDRIVE>:/Program Files (x86) on WoW64
* Explicitly stated the Start Menu sub directory