Ensemble API
Batch predictions can be made from an ensemble
Take more options
Provide debug mode

Turn debug mode on like:

BigML.configure do |c|
  c.debug = true
end

When in debug mode, unsuccessful requests will raise.
Remove debug code
standardize options handling for :timeout and :delay ... otherwise if you set one, you have to set the other too
Merge branch 'rspec3' into ensemble
Update spec
Merge pull request #15 from faradayio/ensemble

Ensemble support
Merge pull request #17 from faradayio/debug

Debug mode
Merge pull request #18 from faradayio/fix-timeout-and-delay-defaulting

Standardize handling for #wait_for_ready options :timeout and :delay
Merge remote-tracking branch 'upstream/master' into evaluation

Conflicts:
	lib/big_ml.rb