Merge pull request #11 from oliverjohnstone/master

Adding Mongodb $in operator
Version bump
Forcing id to string
Adding test to see if data is not referencing input data
Fixing issue were memory-engine would manipulate data becuase it was referancing it

Conflicts:
	lib/memory-engine.js
Adding events for after crud functions and tests

Conflicts:
	lib/memory-engine.js
Merge branch 'master' of github.com:serby/save into dataReferencingFix

Conflicts:
	lib/memory-engine.js
	test/engine.tests.js
Adding new emits to readme
Merge pull request #13 from Joshwlsn/dataReferencingFix

Data referencing fix
Expose the expected type of the ID
version bump
Ensuring type on test
Adding test to ensure nested objects are persisted correctly.
Merge pull request #14 from lukewilde/master

Adding test to ensure nested object properties are persisted correctly.
Adding tests and logic to ensure the memory-engine always returns a string based ID.
Removing debug code.
Merge pull request #15 from lukewilde/master

When manually passing an _id, it was returning it as a number
Version bumb