Make binary verbose

Addresses #610 , might be a starting point if @leostera feels like going to town on this sometime.

Here are a handful of improvements to make the sequelize binary a bit more verbose (including the migrations).

* Set the environment via the command line 46f5caf
  * `sequelize -m -e test` will run in the test environment
* Upon failing to read the `config/config.json` output a more useful error. 4c23c8a
  * Instead of throwing an error, catch it and output if it was a parse or file system issue
  * exit with an error code
* Add `done()` to migration skeletons 6f65e6d
  * I keep forgetting to do this to the `down()` so my migrations hang, I can't be alone, and I think it makes sense for it to be part of the skeleton.
* Output the elapsed time of migrations 61482c0
  * If no migrations are to be run, instead of saying nothing (crickets) it will inform the user that there are no migrations to run.
  * A little bit more information in the migration output, not as pretty as it could be (it would be nice if it stayed all on the same line instead of breaking it into two) but it's not any bigger than the original, and has more information.
* This one is subjective, but I "improved" the copy in the binary output 37244f1
  * I find the term 'undone migrations' awkward because it sounds like it was done, then undone. The term used in other places for a migration which has yet to be performed is "pending" so I stuck that in there.
  * Some of the errors were a bit prickly, so I tried to change them to refer to other commands