Basic tests for #12

Still requires some more extensive tests
Merge remote-tracking branch 'origin/protocol' into basic_primitives
Cherry picking changes from js_improvements required for rgba format changes in protocol
Fixes new tests for rgba
Fixes bug in rgbaDictToColor if alpha is zero

Fixes bug: rgbaDictToColor parses rgba as rgb if alpha is zero
More extensive tests

New tests:
- rgbaDictToColor
- parseFigureMessage: for circles and containers
- Disabled canvas drawing tests using imageDiff due to a bug in
imageDiff
Added shape selecton with red flash to the debugger
Resolved merge conflict with building the debug message
Merge branch 'js_improvements' of https://github.com/CanvasHS/Canvas.hs into js_improvements
Git requirement in test script
Scroll events sending to the websocket and logging of events added
Fixed static to support images
Started implementing mouseDragEvent
Merge remote-tracking branch 'origin/protocol' into js_improvements
Implemented mousedrag
Merge pull request #41 from CanvasHS/basic_primitives

Implemented basic primitives, merge to dev.
mouseDragEvent has correct previous position now
Prevents bubbling of event handlers
js_improvements: support added for mouseDoubleClick events
Fixes #43, turns debug off by default