Remove gulp as a dependency

I've listed out the changes since there are many:

#### README: 
 - Add Travis badge
 - Add link to new example folder

#### package.json
 - Update required node version to >= .9 (gulp requires >= .9)
 - Remove gulp as a dependency
 - Add npm scripts for mocha testing

#### index.js
 - Remove `require('buffer).Buffer` (redundant in es5)

#### test/test.js
 - Update tests to not use gulp
 - Reduce the number of `fs` calls to increase test speed

#### test/expected
 - Add expected result files

#### examples/
 - Add example files 
 - Add example gulpfile

#### .npm/git ignore
 - Update to ignore OSX/Unix/Windows cruft
 - Add .npmignore

#### .travis.yml
 - Add travis file