Add explore method to the engine level stores
to facilitate more efficient querying

This method contains a more efficient find implementation
and it also returns the relevant data that causes the find
to include the matching records. This can be used to pass
data along to a buffer context without having to make
two separate reads to process a buffered find query

Conflicts:
	concourse-server/src/main/java/org/cinchapi/concourse/server/storage/BufferedStore.java
	concourse-server/src/main/java/org/cinchapi/concourse/server/storage/db/Database.java