add gulp and bower to the list of devDependencies

[davemo]

• this allows users to avoid having globally installed versions of these
  modules so that the only thing they need to do to contribute is:

npm i
npm test

[chemerisuk]

@davemo I put all dependencies into separate project https://github.com/chemerisuk/better-dom-boilerplate. Usage of bower is deprecated - the community decided to use NPM for everywhere. And gulp is awesome, you do need to have it to be installed globally :)

[jasonkarns]

I'm 👍 on this. This package requires gulp for any of the npm scripts to function and global installs are an antipattern.

According to the karma config in package.json, this module is also expecting bower to be used as well:

better-form-validation/package.json

Lines 25 to 27 in 6d10c3d

	"bower_components/better-dom/dist/better-dom.js",
	"bower_components/better-i18n-plugin/dist/better-i18n-plugin.js",
	"bower_components/better-popover-plugin/dist/better-popover-plugin.js"