added a new project for tests into the workspace
added Kiwi for testing
added some test on creating operations
added test on engine's apiPath property
added OHHTTPStubs for network requests stubbing
added tests for calling completion blocks
adding request handlers once to OHHTTPStubs
Merge remote-tracking branch 'yas/adding-tests'
update Kiwi and OHHTTPStubs submodules to the latest versions