-- Added _shared_globals.selectedToolchains so we can query the toolchains selected for a given build.
-- Fixing up the Android toolchain so we can point it to a custom location for the Android NDK/SDK/etc.
-- Fixing the Visual Studio project generator so it works with the recent change for building with multiple toolchains.  It still has problems with generating projects with the Tegra-Android platform, but Win32 and x64 work.