Use `logging` module instead of prints in migrater script

I replaced `fail` function printing out to `stderr` with `logger.debug`
(from Python standard library).

Additionally I introduced `info` function that indicates migration
progress.  It simply logs out "Successfully migrated 'TABLE' table",
so that user knows the script is running error-free.
Fixed #104, adds jQuery from CDN.
workshops/models.py: List choices for Person.gender

This is not a free-form field, since we're only allowing 'M' (for
male), 'F' (for female), 'O' (for other), and NULL [1] (we don't know)
in the database.  Telling Django about these choices [2] gets us the
convenient get_FOO_display field and better form UI (drop down
selections) and validation.  The field also sets 'blank=True' [3] to
allow folks to edit their profile without specifying any of the gender
choices.

[1]: https://docs.djangoproject.com/en/1.7/ref/models/fields/#null
[2]: https://docs.djangoproject.com/en/1.7/ref/models/fields/#field-choices
[3]: https://docs.djangoproject.com/en/1.7/ref/models/fields/#blank
workshops/migrations/0027_auto_20141222_0144.py: Explicit person.gender choices

This is the template created with:

  $ python3.4 ./manage.py makemigrations
db.sql: Migrate to person.gender choices

With:

  $ make database
  $ python3.4 ./manage.py migrate
  $ sqlite3 db.sqlite3 .dump > db.sql
Change default logger name in migrater script

It used to be `"__main__"` because that's what `__name__` defaults to
when invoked directly.  Using string name (`"amy-migrater"`) ensures
that logger has it's own recognizable namespace.
Change `migrater.py` verbosity

For now I stick to hard-coded verbosity of INFO messages (ie. every
message with higher or equal severity to INFO will be shown).
Consult https://docs.python.org/3/library/logging.html#levels for the
list of logging message levels.
Merging @wking's updates to gender selection and re-doing changes to migrater.

Instead of `------`, the pulldown for choosing gender should display `unknown`.
Merge pull request #100 from pbanaszkiewicz/morelogging

Use `logging` module instead of prints in migrater script
Merge jQuery from CDN

We need this Bootstrap requirement.  Ideally I'd like a bower.json to
make it easy for folks to download and use local copies.  Kevin Bowrin
has something close in the rest of #105 [1], but it's more complicated
than what I have in mind (with a bower.json and hard-requirement on
Bower instead of Kevin optional-Bower-falling-back-to-CDN).  Merging
7d38239 gets us a working Bootstrap until I have time to put that in.

* commit '7d38239':
  Fixed #104, adds jQuery from CDN.