Merge pull request #118 from paperlesspost/remove-appdelegate-import

remove AppDelegate import from EJJavaScriptView
Fix #117 - safely tear down all background operations when dealloc'ing the ScriptView
Added default viewport for WebGL - see #115
Only present screen canvas when needed - close #115
Fix #116 - baseline for certain glyphs was off by one pixel due to anti-aliasing
Fixed view size for landscape mode
Merge with master