Cadence 0.0.12

Issue by Issue

• Propagate this. #84.
• Use identity operator in check for early return. #82.
• Build callback object in _async.
• Rename arguments property to args.
• Move sizes indent from t/sizes to t/test.
• More tests for fix-up cadences.
• Remove if statement to test for invoke callback. #66.
• Fix cadence return values. #76.
• Fix arity.
• Remove hidden context. #75.
• Remove timeouts. #80.
• Use Error to indicate subsequent error handler. #68.
• Remove wrap option. #78.
• Remove 'use strict'.
• Ensure reentrancy. #74.
• Remove underscore to indicate zero arity. #73.