Adding equivalentMap and equivalentArray matchers. Change includes documentation and tests.
These matchers verify that given arrays and maps are of the same structure and contain
equivalent content. The matchers will verify nested arrays and maps e.g.

{"key" : [ {"nestedKey" : "nestedValue"} ]}
Merge pull request #17 from Offler/master

Adding two new matchers equivalentMap and equivalentArray, documentation and tests included.