Add enforcement for foreign key contraints with sqlite

Fixes bug 1171732

When creating an engine the called can indicate whether or
not to enforce the constraints for sqlite.

Change-Id: I1d5820376f60388c084afea500f807cd25541800
Add middleware to limit size of HTTP requests.

Adds a new RequestBodySizeLimiter middleware to guard against
really large HTTP requests. The default max request size is 112k
although this limit is configurable via the 'max_request_body_size'
config parameter.

Change-Id: I76248feed5c77f678b8a43f364d4f1e0794ab910
Add missing LICENSE file

Don't we need one?

Change-Id: I2b8cdf40dd9493db1f497893939f897c06337c04
Merge "Add missing LICENSE file"
Merge "Add enforcement for foreign key contraints with sqlite"
Merge "Add middleware to limit size of HTTP requests."