Avocado

**Features**
- 230 - The data cache API now supports caching results with arguments

**Enhancements**
- 226 - New `DataField.dist` method for getting a simple distribution of the field data

**Bugs**
- 228 - Fix migration from v2.3.6

**Features**
- 223 - Add `DataField` and `DataConcept` `indexable` field for toggling which fields or concepts are indexed by Whoosh

**Bugs**
- 224 - Fix an unbound variable error

**Enhancements**
- 214 - Add `DataField.random` for returning N random values
- 220 - Add optional `queryset` argument to many `DataField` methods
- 212 - Return cleaned values from DataContext validation

**Bugs**
- 218 - Support unicode in CSV exporter
- 222 - Remove hard-coded `ValuesQuerySet` transform in `QueryProcessor.get_queryset` method

**Features**
- Queries can now be (optionally) shared by username. Sharing features are now driven by [a few settings](https://github.com/cbmi/avocado/blob/master/avocado/conf/global_settings.pyL103-L109)

**Enhancements**
- The admin list display has been updated to order by categories and current status
- Hardcoded admin URLs have been removed to support sub-classing
- A new `sparsity` method has been added to `DataField` which computes the ratio of records with null values to the total count
- Regexp operators has been added to the registry for string-based fields
- Queries using Djago proxy models will now be properly respected due to a change in [modeltree 1.1.8](https://github.com/cbmi/modeltree/releases/tag/1.1.8)

There was a bug observed sporadically with the data category search index template using Django 1.4.x. This was most-likely due to a self include of a template. This behavior was not necessary so it was removed to prevent a recursive include.

**Enhancements**
- `Field` and `Concept` names (and their plural forms) have been corrected to use the `__unicode__` representation of the instance rather than merely relying on the `name` field. This ensures _something_ is returned when doing `unicode(field)` and `field.get_plural_name()`.
- DataField supplementary fields have been added to the admin.