Add bypass for saturate(5%) filter function. Helps issue #1299
Added support and tests for !merge() syntax #700
Syntax changed to !merge(space | comma)

* Syntax changed to !merge(space | comma)
* !merge(space) implemented by Expression instead of Value.
* Added test for lonely property with !merge directive
Fix merge tests when running in phantomjs
Convert property merging to the new agreed syntax of +: