Introducing RGB Script API version 2 and the RGBScriptProperty class.

See documentation.
TODO:
- handle type 'string' and 'integer'
- convert QLC+ script to v2 where possible
RGBScripts: added fill.js as a replacement for fillcolumns/fillrows
RGBScripts: fixed Fill and Stripes rgbMapStepCount
RGBScript: let's start with serious scripting

Added gradient.js
Improved verticalfall.js
Fixed devtool.js to support all colors !
Added empty.js as a starting point to write a script
RGBAlgorithm: added acceptColors property (see documentation)

Verticall fall script doesn't need an end color
RGBMatrix: apply script properties when starting

Added opposite.js as a replacement of oppositerows/oppositecolumns
Cleanup a few comments from new scripts
RGBScripts: replaced v1 scripts moved to qlcplus-extras
RGBScripts: added squares.js

Still a work in progress: it works properly with the devtool but not in QLC+
RGB Matrix Editor: added toggle to preview circles or squares

Renamed stop.png to square.png
Improved Squares and Vertical Fall scripts
Merge branch 'master' of github.com:mcallegari/qlcplus into rgbcaps
Updated changelog and commented squares.js until it works properly
rgbcaps branch merged. Everyone please help with new scripts