Remove build files from git
ignore .DS_Store for osx dev
Warn about throwing primitives

This is no different from synchronous code but this is _oh so very important_ to know when debugging asynchronous code.
Clarify behavior of Promise.reduce when `initialValue` is `undefined`.

See #97.
clear out ref to promise after resolver has completed
style
Add a CONTRIBUTING.md file
add columns style
Give stack traces to primitives and report unhandled primitives
Release v1.0.4
Merge branch 'master' of github.com:petkaantonov/bluebird

Conflicts:
	src/promise_resolver.js