* Remove Python references in Dart math generator
Resolves#2329
Commit in develop branch
* first commit for Thomas
* Created entry for custom-dialogs
Part of issue #1709
* icon.png for custom dialog demo added
Refactor of interpreter demo
* Renamed demos/interpreter/index.html as demos/interpreter/step-execution.html (including redirect), and added demos/interpreter/async-execution.html.
* Refactored code to automatically generate/parse the blocks, eliminating the need for a "Parse JavaScript" button. Code is still shown in alert upon stepping to the first statement. Print statements now write to output <textarea> instead of modal dialogs.
This is based on the JS generator, with a lot of inspiration from Ellen
Spertus's blockly-lua: https://github.com/espertus/blockly-lua
All unit tests pass with Lua 5.3.2.
