Add usercontent template tag to hide data

On the user profile page we need to hide the personal data and edit
controls from the public but show them to the logged in user.

The main benefit of the tag is to make template code that shows
non-public data to only one specific user more self documenting.
Rename audit_extras to auth_extras

Both template tags deal with authorization rather than auditing.
Fix recent edits paging on profile

I removed a key div by accident when I merged the prototype markup.
Merge branch 'master' of github.com:azavea/OTM2
Add a JSONField that translates db strings to python via JSON

Just make a JSONField field:

```
class MyModel(models.Model):
   stuff = JSONField()

...

m = MyModel()
m.stuff['user'] = {'age': 4, 'name': 'Peggy'}
m.save()

```

JSONField does not currently support lookups.
Add config JSONField to instance

Also provides a way to create simple getters/setters. If we want to add
a new top-level setting simply run:

```
advanced_search_filters = _make_config_property(
   'advanced_search_fields')
```

Which will allow you to write and read that property directly from an
instance:

```
i = Instance.objects.get(pk=?)

i.advanced_search_fields = ['field 1', 'field 2']
i.save()
```
Add base for management app

This app will provide administrative tools for customizing user defined
fields and permissions.
Provide support for injecting urls via local_settings.py

This will be useful when we want to merge in private apps.
Merge pull request #196 from jwalgran/topic/usercontent-tag

Add usercontent template tag to hide data
Merge pull request #206 from ahinz/topic/instance-config

Topic/instance config
Add utility functions for setting and getting visited instances
Use last instance visited for non-instance "Explore Trees" link
Made utility function names consistent
Ignore the cloud management app
Don't get the boundaries and species lists for the map template.

Since typeahead.js prefetches these using AJAX, the template no longer needs them.
Have User.save pass it's *args and **kwargs to save_with_user

Fixes callling client.login() from a test method.
Add extension point for installed apps
Merge pull request #207 from maurizi/topic/storeInstances

Topic/store instances
Merge branch 'master' of github.com:azavea/OTM2
Merge pull request #211 from ahinz/topic/create-management-app

Topic/create management app