Add live editor

[kitsonk]

This PR provides a new LiveCodeController and LiveCodeExample which provides the ability to embed examples within a web page that are editable and runnable.

[kitsonk]

Here is a video of it in action:

[codecov]

Codecov Report

Merging #33 into master will increase coverage by 0.97%.
The diff coverage is 74.11%.

@@            Coverage Diff            @@
##           master     #33      +/-   ##
=========================================
+ Coverage   66.53%   67.5%   +0.97%     
=========================================
  Files          17      29      +12     
  Lines        1007    1779     +772     
  Branches      239     418     +179     
=========================================
+ Hits          670    1201     +531     
- Misses        337     578     +241

Impacted Files	Coverage Δ
src/widgets/Editor.ts	73.52% <100%> (ø)
src/widgets/LiveEditor.ts	100% <100%> (ø)
src/widgets/Runner.ts	97.65% <100%> (ø)
src/project.ts	75.77% <38.8%> (-11.56%)	⬇️
src/LiveCodeExample.ts	90.47% <90.47%> (ø)
src/LiveCodeController.ts	98.14% <98.14%> (ø)
src/widgets/ActionBar.ts	89.47% <0%> (ø)
src/widgets/IconCss.ts	100% <0%> (ø)
... and 8 more

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[nicknisi]

This code looks good! We need to figure out how this can be used alongside the current export of this project or how we can change things to make them both work.

[kitsonk]

@nicknisi I think I will get time this week to re-base it and submit something. How we get it to work along side the other export, I will see if it is obvious when I rebase it, if not, well I will at least try to think of an approach.