Don't silence test errors

This moves the test logic from the makefiles to a shell script, because then we can still clean up the `liveassets` directory without  needing to silence the errors thrown by `grunt test`.
In that case, remove the hyphen and add -k to the make command to keep going the rule but treat the failure as a failure.
http://www.gnu.org/software/make/manual/make.html#Errors