Feature: Being able to run tests through flow

[anissen]

It would be nice to be able to run (unit) tests through flow. That is, to define a test command that can be executed through flow (e.g. flow test, flow test web) and through _sublimeflow.

In the simplest case, the functionality might to execute a command like haxe -main UnitTest.hx -x UnitTest.n -lib mohxa. The flow file format for doing this could be something like:

{
  project : {
    name : 'empty',
    version : '1.0.0',
    author : 'luxeengine',

    app : {
      ...
    },

    build : {
      ...
    },

   test : {
      main_file: 'src/test/UnitTest.hx',
      dependencies : {
        mohxa : '*'
      }
   }

  }
}