Renamed site_make -> drushsubtree.

	modified:   README.md
	renamed:    site_make.drush.inc -> drushsubtree.drush.inc
	renamed:    site_make.example-dev.yml -> drushsubtree.example-dev.yml
	renamed:    site_make.example-prod.yml -> drushsubtree.example-prod.yml
Fixed bug detecting config when only a single config file is available.

  For associative arrays, use array_shift.

	modified:   drushsubtree.drush.inc