Correct argument type for dataastore's `find`
Add lots of tests that don't work
Add request filters object

This generates appengine filters from the request object by parsing
the querystring.
Merge remote-tracking branch 'origin/master'
Restore sbt to linux-dev GAE SDK location

This is because for most devs here, this is the correct location.
Add authentication to the project

It now uses the IdentityApiClient library to authenticate users using
a GU_U cookie or a GU_U request parameter.
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/main/scala/com/gu/idstore/JsonStore.scala