HTTPS fix.

Digg Digg stylesheet was being blocked on our website with enforced HTTPS. This fixes that, as well as improves upon how the stylesheet should be loaded based on WordPress best practices (using the wp_enqueue_scripts action hook).

Also removed a few lines of code that checked for a few core constants. Seems extremely paranoid. (Sorry for the whitespace differences. My editor gets rid of all whitespace on blank lines and at the end of lines).