Improve docs on starting a server

 - Users should be aware that they need to make sure their server logs
something, because following tasks will not be started otherwise (e.g.
watch etc.)
Merge pull request #75 from nicroto/master

Improve docs on starting a server
Bugfix

moved from grunt.util.spawn to node spawn to properly catch syntax
errors.

fixed tests
implemented #48
Added documentation

For the new logs feature