Script to set up Windows build dir as KODI_HOME

This change adds a new batch file, make_kodi_home_symlinks.bat, which accepts one cmdline argument: the path to the build directory (e.g., kodi\project\VS2010Express\XBMC\Debug).

This script creates symbolic links in that directory to all of the directories and DLLs that Kodi expects to find via the KODI_HOME environment variable. This allows Kodi to be run from the build directory without KODI_HOME having been explicitly set.

Being able to run Kodi from the build directory without any special environment variables set is important for debugging Kodi when launched via the Windows shell (e.g., as an auto-play handler for inserted media, such as DVDs).

Unfortunately, due to the default user privileges on WinVista+, normal users cannot create symbolic links, by default, so this script must be run with admin privileges.