changed section on RDF + added JSON-LD info
Extensions: using multiple ones + suggesting 3 new in TODO
fixed typo :S
Merge pull request #44 from elf-pavlik/master

changed section on RDF + added JSON-LD info
Bumped v0.6.12 and updated HISTORY.md.
created a helper function for initializing a 'db' instance.

added another argument to the constructor that is a callback for when the indexDB onStoreReady state/function is called.

also made the constructor work if there are only 2 arguments and one of them is supposed to be the 3rd argument callback function.
Added unit tests and general polish.
Merge branch 'boxxxie-master' into v0.7-wip

Conflicts:
	lib/levelgraph.js
	package.json
	test/triple_store_spec.js
Added one more test for the ready callback.