Allow server-side LESS configuration

+ Added new, generable grid system, which allows customizable grid
(column numbers, class names, etc.)
+ The template is now completely based around 3 main colours (primary,
secondary, tertiary), and the rest adjusts to those using LESS
functions.  These can be adjusted in the template configuration in
Joomla
+ Update LESSPHP to resolve many bugs
+ Allow colour pickers using new HTML5 input, with fallback for IE6+
+ Mass overhaul to mixins.less.  Fix for Mozilla border-radius.  Fix for
IE8- on gradients.

* Styling fixes: responsive menu correctly nides now.

- Remove unneeded LESS files
- Remove unneeded configuration parameters in config.xml
- Comment out media query JS shipped by YouTheme.  It seems to be buggy,
so I will leave it to the template creator to deal with that.