Added browserify support

[craigh411]

Added the babilify transform for browserify in packge.json so the src files can be transpiled in browserify projects.

Fix or Enhancement?

Browserify applies transforms on a per-module basis and doesn't appear to allow global transforms, meaning that babelify needs to be declared in the modules package.json in order to transpile the ES2015 code in src.

In order for a browserify user to transpile the code, they would need to install babelify and babel-preset-es2015 and add a .babelrc file in the root of their project with the following code:

{ 
"presets": ["es2015"]
}

I think you could get away with explaining that rather than creating a dependency for babelify and babel-preset-es2015 because many vue/browserify users will already have their projects set up this way.

[codecov]

Codecov Report

Merging #51 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master    #51   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines          75     75           
=====================================
  Hits           75     75

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