Added new warning level "Everything" which turns on all available
compiler warnings. Updated "High" and "Extra" to reflect actual
differences in emitted compiler flags.
As discussed numerous times, get rid of the submodule approach for core modules and just included the sources directly in the main repository.
I have no idea how this will play with existing working copies. It might be necessary to [manually clear out the existing submodules](http://stackoverflow.com/questions/1260748) first.
