Remove examples

These were just to show some examples working. We're not using this anymore.
Use a simpler default instance.center for tests

Point(0, 0) makes it easier to write tests with simple mental
math. For example, it's easy to tell that (2, 2) is further from (0,
0) than (1, 1) so the tests are more readable.
Factor out reusable logic in BoundaryViewTest
Add a junction table for instances and boundaries
Modify README file to add header
Add a view for boundary name autocomplete
Modify boundary_autocomplete view to accept param

The user can pass in a maximum return value to override the default
of 10.
Change return type of boundary_autocomplete

Return a list of dicts instead of a list of names.
testing build, again
Refactor BoundaryViewTest class to support more tests
Add test for boundary_autocomplete max_length param
Merge pull request #42 from steventlamb/topic/boundary_autocomplete

Topic/boundary autocomplete
Merge pull request #44 from azavea/testBuild

Modify README file
Merge pull request #41 from ahinz/topic/remove-example

Remove examples
Add GPLv3 license
Add in filter parser

Adds code to parse filters according to the following syntax:

    literal        = json literal | GMT date string in 'YYYY-MM-DD HH:MM:SS'
    model          = 'plot' | 'tree'
    value-property = 'MIN' | 'MAX' | 'EXCLUSIVE' | 'IN' | 'IS'
    combinator     = 'AND' | 'OR'
    predicate      = { model.field: literal }
                   | { model.field: { (value-property: literal)* }}
    filter         = predicate
                   | [combinator, filter*]

In particular, this commit provides code (and tests) for transforming
filter strings into query objects.

This commit does not actually provide any specific filters (or tests) by
itself. Those should be added and tested as needed.
Merge pull request #45 from ahinz/wip/filter-parser

Add in filter parser
Merge pull request #46 from ahinz/fix/add-license

Add GPLv3 license
Don't call standard login hooks

Since users are "audited" they require a call to "save_with_user". The
default hook here attempts to do something like:

user.last_login = today()
user.save()

Which causes an exception

This fix isn't really permanent, but it does enable login with the
django admin. In the future, we'll have to figure out how to handle this.
Disable the admin interface in production