minor improvements in machine list

* also listen to `hubot show machines`
* put mac address in ticks to format it as code
add status badge in README

and indent the two installation steps
chore: replace `grunt-bump` with `grunt-release`

So I can publish to NPM Registry with one command: `grunt release:patch`
docs: changes needed for publish

* replace gitlab with github
* update urls in [package.json](/package.json)
* update [README](README.md),
	* replace build-badge
	* update install instructions
* init a empty [changelog](CHANGELOG.md)
test: fix `npm test`, Travis does not Grunt
style: convert indention *.coffee to tabs/4 spaces
refactor: move sending packages to a new function
feat: listen on HTTP to wakeup machines

disabled by default, to enable it set env `HUBOT_WAKEUP_HTTP_ENABLED`
docs: update CHANGELOG.md
Release v0.0.3.