bundle js with browserify

[andrenarchy]

This PR introduces browserify:

• split big src/index.js in many small files in src/js/
• build source map
• we can now use npm modules, see example in src/js/directives/ipv4Address.js
• add ipv4 validation (subnets and ipv6 still missing, see add missing field validation #14)
• change gh-pages to dist (gh-pages is only a good name for the test deployment)

[geirkairam]

:/ the last commit is almost the same as I did in #14. but in your commit validation for fields "mesh on lan" and "client subnet" is missing. in addition translations are missinge.

do you mind to remove your last commit merge this pull request to master and then merger master to branch 14-add-missing-field-validation and work on validation issues there?

[andrenarchy]

@geirkairam feel free to modify/replace the ipv4Address validation. :)