Adds property overriding so more coarse properties override more granular ones.

* E.g. 'border-top' overrides 'border-top-width' and 'border-top-color'.
* Another example is 'margin' overriding 'margin-(bottom|left|right|top)'.
Adds reducing non-adjacent selectors.

* Removes repeated properties in same selectors which are not next to each other.
* E.g. '.one{color:red;margin:0}.two{color:#fff}.one{margin:1px}' will become '.one{color:red}.two{color:#fff}.one{margin:1px}' because margin is repeated.
Adds `--no-advanced`/`noAdvanced` switch to disable advanced optimizations.