Changes

: Fix transparency in <TT>copy()</TT> function. Ticket @[https://processing-js.lighthouseapp.com/projects/41284/tickets/1055-copy-doesnt-handle-transparency-properly lighthouse]

: When using copy() on an image with transparency, the transparency overwrites the background color. See the screenshots to compare against p5. The image is a red splatter with transparent background and the background is green.

* Helpful tips

: From [http://processingjs.org/reference/loadImage_ processingjs.org] DOM security will not allow you to load images file:/// URIs. This security can be overridden in Firefox in about:config, by changing security.fileuri.strict_origin_policy to false.