Add CasperJS tests for `merge_cell_above()` and `merge_cell_below()`.
jstest moved to new place, closes #3125
make casperjs test suite pass again
less convoluted way of grabbing output
consistently get the first cell
include the # of active kernels in server info
simplify prepare_controllers logic
added javascript section with casperjs requirement
JSController working, `iptest js` runs casperjs
start and use notebook server for js test suite
--no-browser flag to js tests notebook server
workaround for travis-ci/travis-cookbooks#155
don't try to delete notebooks

this method wasn't currently working, and though we should put a working
method there as a utility, it isn't strictly necessary, since the whole
directory will be deleted
use a temporary directory for js tests
quieter notebook server output for js test suite
updated js tests README, --port= now optional
more informative message on server timeout
add Pierre Carrier's PPA for CasperJS & PhantomJS
travis needs -y flag
pep8 style function names