Adding notes to README to direct effort where it is most needed.

Lots of small features could be added to Amy, but we need to concentrate on things that will make it usable by non-programmer admins in January 2015.
Updating notes to README
Starting to build an instructor lookup form
More work on a form to find instructors near a location
Switching trainee status to enumerated field
Cohort details page shows participants with status
Bug fix: cohort venues not being recorded correctly.

1. Fixed bug in `migrater.py`: cohort venues were being stored as strings, not site IDs.
2. Updated db.sql to match.
First working version of instructor lookup form.

1. Fixed bug in migration script to populate people's airports correctly.
2. Regenerated `db.sql` accordingly.
3. Fixed airport search logic in `match` view.
4. Modified template to display correctly for both `GET` and "no matches found".
Added have_qualifications method to Person QuerySets.

This commit adds a new method to Person QuerySets called
have_qualifications. It takes a list of Skill objects and
returns only those Person objects which have ALL of the
listed skills. I also added a usage note to the "match" view.
Merge pull request #3 from rbeagrie/instructor-search-form

Added have_qualifications method to Person QuerySets.
Adding checkboxes for skills dynamically.

The set of skills instructors have may vary dynamically, so the instructor matching form builds the list on the fly.
migrater.py: Use datetime.date.today() to find the current date

Instead of hardcoding it in the Makefile.  This reverts the portion of
4c6fa04b (Switching trainee status to enumerated field, 2014-12-15)
that added the TODAY argument.

The .isoformat() call is because I don't know if cohort_start[cohort]
is a string or a datetime.date.  Since we were using string
comparisons before, using a string here seemed safer.
Merge pull request #4 from wking/get-today-automatically

migrater.py: Use datetime.date.today() to find the current date
Merge pull request #78 from gvwilson/defining-enumeration-for-instructor-training-status

Defining enumeration for instructor training status
Filtering by qualification (incorrectly)
Debugging
Filter persons with skills using qualification as an intermediate table.
Correcting filter bug in instructor skills query
Merging from master
Merge pull request #80 from gvwilson/instructor-search-form

Adding instructor search form