7.0.0

• rewrite core.js to be much faster (exposes some internals via randomly named _ prefixed variables)
• Update to asap 2.0.1 internally
• add Promise#finally
• add support for "tail recursion" providing no reference to the root promise is maintained. This may change callback ordering, but that ordering was previously unspecified.
• remove support for domains from default build
• add a special build for domains
• add a special build for environments that implement a sufficiently efficient setImmediate that including asap is unnecessary.