don't add ~/.emacs.d/ to load-path user src subdir

Very new versions of Emacs now complain about adding the base of the
~/.emacs.d/ directory to the load path.  Since the starter-kit suggests
placing source files into ~/.emacs.d/src/ instead of directly in
~/.emacs.d/, we may as well remove ~/.emacs.d/ from the load path as the
new Emacs warnings recommend.

I apologize if this change breaks anyone's existing config, although it
should be an easy fix, simply move all required .el files into the src/
subdirectory.