Reformat controller

[voodoos]

Not for merging yet

I would like to start a series of opinionated code cleanup:
Now that we use babel es6 features can be used without restrictions.

Changes

Change I made for now, only in controller.mjs

• Use new class def for the controller.
• Remove useless getter/setter: if you don't need fine control, default js setters and getters are ok
• Change numerous if sequences by switches. This is very opinionated, I can rewind if needed.
• Check with jshint and reformat with javascript prettier. We might want to add these tools to the build chain.

Questions

Most of the key shortcuts do nothing, is that expected ? (zoom, rotate etc)
What is the difference between "t" and "T" ?

[panglesd]

Yes, lots of reformat are needed :)

• I agree with the use of class from es6,
• I don't mind the switch instead of if, though for me they are the same,
• rotate used to work. It would be easy to make it work again, but I want a better way of dealing with it first, and it's clearly not a priority
• zoom works once you enter the first slip, that is after the first next(). This is because I haven't yet implemented a start() method to engine.
• I need to rename showToC to buildToC and then write showHideToC which is what will be called by pressing t. Pressing T rebuilds the table of content in the DOM and should now be deleted.