generate bower.json

Mentioned in issues: https://github.com/jrburke/requirejs/issues/975
Content of the file:
```json
{
  "name": "requirejs",
  "version": "2.1.9",
  "homepage": "http://requirejs.org",
  "authors": [
    "jrburke.com"
  ],
  "description": "A file and module loader for JavaScript",
  "main": "require.js",
  "keywords": [
    "AMD"
  ],
  "license": "new BSD, and MIT",
  "ignore": [
    "**/.*",
    "node_modules",
    "bower_components",
    "test",
    "tests"
  ]
}
```