Add get API methods for getting item information.
Removing available collection item methods.
Changes from code review.
Adding missing headers to support cross-domain Content-type modification.
Merge branch 'master' of https://github.com/harvard-library/librarycloud_collections

Conflicts:
	src/main/java/edu/harvard/lib/librarycloud/collections/CollectionsAPI.java
First cut of authorization code.
Completed authorization code.
Edits from code review comments.
Merge pull request #4 from rholcombePod/master

Add collection item retrieval methods.