* Use a simple but (hopefully) very reliable way of detecting whether runtimes need to be installed: Check for an uninstaller entry for the runtimes.
* Clean up from most, hopefully all, 2.x alpha and pre-release installers we have previously put out.
* Also clean combinations of 1.x and 2.x pre-rel versions installed on top of each other.
* TODO: List all completed translation files for installation.
Originally committed to SVN as r3058.
