Fix Travis tests by not supporting node 0.10 and node 0.12

[jimmyhchan]

Hello 2017 from 2015. #146 added a workaround for a bug shown in Node 8. For sake of semVer we should bump major (or if we insist on keeping with the previous borken tradition of breaking changes in a minor) and require Node 4+.

• Do a semver friendly bump of package.json version
• Remove failing 0.10 and 0.12 Travis tests
• update docs
• mimic changes in dustjs-linkedin
• update package.json engines, update dustjs peer dep to this new major/minor
• push both around the same time.