Improve test speed/source maps/output

[Goaman]

Speed

The tests take quite some times to compile.

Run in parallel

https://www.npmjs.com/package/karma-parallel

Sourcemap

In the "debug" tests: (i.e. npm run debug),

• Sourcemap does not work properly
• Sourcemap are slow to load in the chrome dev tool (chrome load all file from all sourcemap)
  • We might want to compile multiples js files with multiples sourcemap rather than one big file.

No output

For yet unknown reason, when using npm run test and changing a file, the tests compile but does not output the result.

[Zynton]

@Goaman Isn't this handled by #238 ?

[Goaman]

We can still tries to make them faster and have better sourcemap for the npm run debug. So I would let this issue open.