chore(tests): migrate all tests to requirejs structure

during the restructuring of the code, I did not leave all migrate
all tests to the new structure, clearing that up now
feat(engine): add engine module, provides api for the engine functions

should makes it a bit easier to use without internal knowledge,
only basic "startInstance" for now
chore(grunt): add grunt to do optimization

the default task will create a single minified js file
with the engine module and it dependencies for use in requirejs
environments