Install clang-3.6 to VM
Install clang-3.6 to VM

Suppress warning message:

  Starting with io.js 3 and Node.js 4, building native extensions requires
  C++11-compatible compiler, which seems unavailable on this VM. Please read
  https://docs.travis-ci.com/user/languages/javascript-with-nodejs#Node.js-v4-(or-io.js-v3)-compiler-requirements.

yuku-t/textcomplete