this commit begins the server data source

- some apis on the server config object for creating(not done yet) data sources, and listing server side data sources
- some functions for smart downsampling of data sources
- tests for remote data capabilities
- serverconfig object modified to use requests sessions, and pass api keys and such into the session object
- views added to server for remote data

currently we would need https://github.com/ContinuumIO/ArrayManagement in order to run all server tests
addressing comments by @damianavila
Merge pull request #446 from ContinuumIO/feature/data_directory

Feature/data directory