Fixed Comments, Updated/Added Mixins

Added additional forward slashes to a select amount of comments to
prevent them from being compiled. Few comments were left as-is,
including RESET, TWEAKS, and MAIN, because they are required to divide
and organize content in the generated CSS file.

Mixins were modified to allow for the optional use of additional
arguments in certain properties, such as box-shadow.  A nobleed mixin
was added to assist border-radius, in that colours can bleed outside of
rounded corners of elements occasionally.