tweak cyclomatic complexity jshint config
add Script#isPushOnly()
Merge pull request #694 from maraoz/add/interpreter

add Script#isPushOnly(), for script evaluation
Refactor transaction to match new API

* Refactor transaction into a different subfolder
* Added a lot of tests for sighash and transaction serialization (from
  reddit's and Ryan X. Charles' `fullnode`)
* Drop "only" from sighash tests and consolidate logs
Split buildPKH arguments, add Copy constructor on publickey