Migrii/blanket — pull request #195 by tmrudick (2013-01-17 23:17:02+00:00)
Title: Allow function as pattern value

I have a scenario where a regular expression or simple string matching is not sufficient for determining which files to instrument. I've added support to pass a function as the pattern parameter so that I am able to run more advanced logic to determine which files to instrument.

Usage would be:
```javascript
blanket.options("filter", function(filename) {
if (filename.length > 8 && process.env.NODE_ENV === 'test') {
return true;
}

return false;
});
```