Experimentally modified the data store to work entirely based on pickled files in the filesystem.

Hoping this will fix some of the issue we're having with PyTables/HDF5.
Updated pickle integration to the latest Pandas API.
Merge branch 'revamp-api-docs' into pickle-datastore
Merge branch 'revamp-api-docs' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merge branch 'master' into pickle-datastore
Merged branch 'pickle-datastore', we'll keep both data store implementations together for now.