(maint) Fix bugs in _check2 and add function to link dotfiles

This commit introduces a new function to /Dotfiles/setup/_check2
to link /Dotfiles/src/ to the home directory. This commit also fixes
bugs associated with starting setup scripts in the /Dotfiles/
directory by way of the Makefile.
Merge branch 'maint/addMakefile/use-tests'

Conflicts:
	setup/_check2

This merge resolves a 2-line conflict in the
_check2 help function message.