made sure to split comma groups only once, reduced and simplified code for both the resolver building and the differentiation between single and multi selector strings (comma separated), merged internal 'compile()' and 'compileGroup()' methods
made sure to split comma groups only once, reduced and simplified code for both the resolver building and the differentiation between single and multi selector strings (comma separated), merged internal 'compile()' and 'compileGroup()' methods

dperini/nwmatcher,dperini/nwmatcher,dperini/nwmatcher