Deleted if statement that was causing choropleth bugs

Not sure what this if statement was doing here -- however,
it was causing a bug that was preventing demographics
from being re-applied as choropleths so I took it out.

Testing has not revealed any regression as a result.
Replace compactness specific avg calculator with general one

This replaces the calculator specific to compactness features
to a more general one that can be used for any generally
continuous set of features.
Moved this to end of mapinit - only seems to be required for new maps

This event listener/trigger was causing some buggy behavior where on
changes in zoom and thematic map for districts were canceling each
other out and removing choropleths.

This seems to be required only on map initialization, so this just gets
called at the end of the mapinit function, once instead.
Add a function to make choropleths for any 'continuous' calculator

This abstracts away the compactness specific choropleth for compactness
into a more general function that will work on any calculator whose
output is a set of continuous (or close to atleast) scores.
Add logic for modifying map legend for adjacency calculator
Modify WFS method to use cached scores if available
Made adjacency optional (minOccures now zero)
Make adjacency a fully optional calculator

This makes a few changes to allow for true option of using
adjacency.

- a setting is written to settings.py depending on if
adjacency is used
- adjacency calculator is optionally used in computing
district features for choropleth
- dropdown selection for adjacency is optionally displayed
Fix various redis memory issues
Add convex hull legend and option to callback
Add convex hull as option in dropdown for district choropleths
Add convex hull scores to geojson returned
Make convex hull choropleth optional

- Add settings flag if convex hull calculator
is added to score functions in config
- Optionally display convex hull option in map
layers
- Use settings flag when building geojson response
for WFS/choropleth
Merge pull request #443 from notthatbreezy/topic/adjacency-convex-edits

Adjacency and Convex Hull Calculator Edits