When a client is created set host to result of "find_localhost" if none is provided.  Fixes #33.
More idiomatic nil check.
Create spec tests for host defaults.
Tailor style fixes.
Move test_events to rspec, and utilize VCR to get rid of sleeps.
Move tags test to Rspec.
Just use the one dog client.
Move mocks to before(:each) just for the tests they affect.
Use newer syntax for expecting mock to receive a method call.
Merge pull request #35 from DataDog/default_to_localhost

Default host to result of "find_localhost" if none provided