to make double clicking on touch devices easier a double click is now triggered when two mouse clicks occur within 500 milli seconds and closer than 50 pixels together
Limited the double click fix to touch devices.
* Changed the trigger distance between touches from 50 to 20.
* The trigger distance now takes devicePixelRatio into account.
Improved comments
Merge branch 'master' of https://github.com/kanaka/noVNC into doubleclick
Merge pull request #283 from samhed/nomousedrag

Fixed so that viewportDrag works even if no mouse button is selected.
Merge pull request #272 from samhed/doubleclick

Allow for double taps to trigger double clicks even if the second touch is a slight bit off
Merge branch 'master' of https://github.com/kanaka/noVNC