Merge pull request #208 from excaliburjs/dev-josh

adding getGlobalX and getGlobalY back
adding getGlobalX and getGlobalY back

returned from the void, forever changed
fix parent to scene
Merge in scene fix
Close #210 Distinguish between mouse buttons with native event, Change sample-game to sandbox
Change opacity effect to take values from 0-1.0
Merge pull request #213 from excaliburjs/dev-erik

Merge fix for #210, and opacity effect fix
added opacity to actors

closes #102 add opacity option to actors