Added ability to tell bower to ignore specific packages

Example:
```javascript
{
  "suppliedDependencies": {
    "jquery": true,
    "jquery-regex": "jquery.*"
   }
}
```

If a package name isn't found in the suppliedDependencies object, it'll attempt to do a regex check using any strings as regex search patterns.

Any packages found are logged out as "skipped."

Related: #927