Adding PHP 5.6 to build matrix.
Adding PHP 5.6 to build matrix.

m4rcsch/lithium-core-library,graphis/lithium,UnionOfRAD/lithium,wbeater/lithium,davidpersson/lithium,datachand/lithium,muyehub/lithium,davidpersson/lithium,pixelcog/lithium,whowgames/lithium,jails/lithium,wbeater/lithium,jails/lithium,m4rcsch/lithium-core-library,muyehub/lithium,graphis/lithium,datachand/lithium,UnionOfRAD/lithium,whowgames/lithium,pixelcog/lithium