fix avatar handling and create schema
filter permissions for containers in handlers

define is_true and has on base.RequestHandler
fix test_collection.py

use tempdir custom module instead of tempfile
fail with 400 when ObjectIds are not valid
check existing schemas against a list at startup
add json schema draft 4 specification
give a more detailed error message for keys mismatch
remove upload method in core.py = dependencies (util.upload_ticket +
json schema)
remove search call + method = schema

https://github.com/scitran/api/wiki/Data-Model

check keys in requests from schema

https://github.com/scitran/api/pull/47/files

add timestamps to files
do not cache container in the storage class

remove old code from Container class

perm_checker is now a function that returns a decorator to allow more complex logic

introduce dao layer to handle db interactions for lists
use permissions checkers to validate queries

created route to handle roles get, post, put, delete for groups