macOS os.getversion() improvements
macOS os.getversion() improvements

* Use system property list to retrieve current accurate system version
* Add description for latest versions

premake/premake-core,starkos/premake-core,premake/premake-core,premake/premake-core,premake/premake-core,dcourtois/premake-core,dcourtois/premake-core,starkos/premake-core,starkos/premake-core,starkos/premake-core,starkos/premake-core,noresources/premake-core,dcourtois/premake-core,dcourtois/premake-core,noresources/premake-core,noresources/premake-core,dcourtois/premake-core,noresources/premake-core,dcourtois/premake-core,premake/premake-core,dcourtois/premake-core,noresources/premake-core,premake/premake-core,noresources/premake-core,starkos/premake-core,noresources/premake-core,starkos/premake-core,premake/premake-core