Gruntfile generation (will replace Makefile)

We're creating a gruntfile which tasks will replace the current
Makefile.

Not finished yet. Current grunt tasks:
- grunt build: Generates a build in debug mode
- grunt test: run tests

Important things on this commit:
- Updated handlebars version
- before using it: npm install & bower install
Added build min and build debug tasks to grunt

Now we can execute:
- grunt build: will generate both minified and not minified build files.
You can call it with targets "min" and "debug". Example: grunt build:min
- grunt buildMin: will generate minified version
- grunt buildDebug: not minified
updated minified build version
Added less task to grunt
Gruntfile simplified

renamed tasks and removed targets
Added clean task to gruntFile
gruntfile: extracted variables

also added clean as build task