add composer component package

adds support for [component](https://github.com/componentjs/component) and [component installer for composer](http://robloach.github.io/component-installer/)

tested with composer custom repo definition in `composer.json`:
```json
    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/glensc/blockui"
        }   
    ]
    "require": {
        "components/jquery-blockui": "*@dev",
```

after PR merge, probably should:
1. create new git tag (f.e `2.66`) in blockui and push it to github (don't forget to [update versions in source](https://github.com/malsup/blockui/commit/761d965dd43f2a190d91418a09fc03e7db0d5a66))
2. register package on packagist.org