Merge gcodeInterpreter optimizations from daid/Cura
Don't store layers or path points to save memory
Increase progress callback to every 1000 lines.

The processor handles 2500 lines per second on a 700MHz pi so as a baseline
that's still 2.5 updates per second.
Removed commented out and unused code
Merge branch 'CapnBry-gcodeinterpreter-upstream' into devel
Refactored ui.js into single files, cleaned up js folder

TODO: minimizer for merging all files belonging to the actual app into one
Allow sending temperature updates with enter

Also some refactoring.

Closes #208.
Merge branch 'upstream/devel'