Added single quoted strings support to stylus mode.
Created a syntax table for Stylus mode.
Also, threw away kill-all-local-variables. I don't see any point in
Decimal point can be part of a constant.
Constants can have values with decimal points: eg. 1.2em or 50.5%
Improved Stylus comments syntax highlighting.
Since Stylus supports both single line ("//") and multi line ("/* */")
comments, I modified the syntax table so that it supports both comment
I also initialized the stylus-font-lock-keywords variable using defvar.