Add simple scripts to generate reports
Merge pull request #66 from edx/sarina/scripts

Add simple scripts to generate reports
Enable DbModels to override defaults based on context
To enable inheritance and perhaps other context-sensitive fns
Test kvs whose default changes on subsequent context calls.
default raises KeyError rather than NotImplementedError
Fix spacing
Pass key to KeyError instances
Remove ide auto-spacing of assignment
Merge pull request #67 from edx/dhm/default_function

Enable DbModels to override defaults based on context
cast default from_json
Test default's use of from_json
Backfill more tests of json conversion
Merge pull request #68 from edx/dhm/default_from_json

cast default from_json
Make Runtimes and model_datas singleton objects

These both now take XBlocks are the first argument in most methods, and
uses the ids from the block the method is operating on, rather than
baking scope ids into the runtime and model_data objects.

[LMS-827]
Remove experimental AnalyticsDb and progress publishing code
Merge pull request #63 from cpennington/singleton-runtime

One Runtime <-> Many XBlocks
Split xblock.core into several smaller files
Rename ModelType to Field
Rename ModelData to FieldData
Merge pull request #64 from cpennington/smaller-files

Split xblock.core into smaller files, and rename ModelType to Field