Changed Binary to extend Buildable.
Added read-only NativeBinary.toolchain property, to allow conditional configuration based on the toolchain being used to build the binary.
Always register the gcc and visual c++ toolchains, to allow configuration logic to look up the toolchain without caring what the current platform is. The visual c++ toolchain implementation is always considered unavailable when the current operating system is not windows.

Also renamed the GCC toolchain to 'gcc' instead of 'gpp'.
Changed DefaultToolChainRegistry.getDefaultToolChain() so that it is not lazy.
Give the ide import performance tests a little more time for the 'small' project.