Initial implementation of requests.
Merge branch 'origin/develop'

Conflicts:
	src/main/java/org/ndexbio/rest/services/NetworkService.java
Merge branch 'origin/develop'
Updated schema to accomodate Requests.
Updated Network object to move properties to top-level properties.
Added (de)serialization of Requests.
Fixed unit test.
Interim commit.
Finish requests