WIP Grunt automation

Let's introduce some Grunt tasks so we can automate things:

- internationalization
- versioning
- deployments
- minification
- build
- readme file creation

Should address #444 and #464 hopefully

Move plugin files into `src` subdir and symlink. Build process will create zip under `dist`
Remove submodules ( use bower for colorbox and composer for hm-backup )
This is much cleaner as only the actual plugin files are in the plugin folder.

Instructions for later:

Developers will need to do `ln -s backupwordpress/src/ bwp-dev` , also the pro addons will check for that on activation. Previously they checked for `loader.php`

Colorbox is now a bower module, but still at same path, so nothing changed really. It will be included in repo. 


the build process will delete all the `.git` and other cruft added by composer and bower

We'll generate a MD readme with `grunt-wp-readme-to-markdown`, and move it up to use for the repo readme

Added `faq.php` which contains the translatable strings. A grunt task extracts the strings into a partial `faq.txt` which is then concatenated with the other parts of the readme file. This way, we can include `faq.php` for the help tab instead of polling the WordPress API.