Watch for supporting .less files

[jhafner]

Currently, when you change a .less file that's in the css directory (/themes/core/css), Motif sees it and generates an updated .css file of the same name. However, when you modify a .less file that's not in the root css directory (but that's referenced by the main .less file) it doesn't update the main .css file.

Example:

• /themes/core/css/template.less -> compiles to template.css when changes are detected.
  ** /themes/core/css/includes/reset.less -> @include'd at the top of template.less. Changes do not get compiled to template.css when this file is modified.

Two ideas:

1. Have Motif watch the css directory and all subdirectories for .less files, but only recompile files in the root css directory when a change in any of them is detected.
2. Have a Motif param that has Motif only check .less files in the root css directory, or all .less files in the root css directory or subdirectories.