move parseAndModify to _blanket

This was required to allow me to use requireJS and mocha at the same time. I use browserify to get falafel ready for the browser, with the consequence that it doesn't set window.falafel. So I need my requirejs.config to look like this:

```shim: {
  blanket: {
    deps: ['falafel', 'mocha']
    , init: function(falafel) {
	  var blanket = window.blanket;
      blanket.parseAndModify = falafel; // this is the line that wires things up and requires this change
      blanket.options('existingRequireJS', 'true');
      blanket.options('filter', '/src/');
      blanket.options('antifilter', '["/test/","/lib/"]');
      return blanket;
	}
  }
  , 'blanket-require': ['blanket']
}```

It should be noted, of course, that my blanket.js for the browser is a concatenation of a number of files, in order:
  * src/blanket.js
  * src/blanket_browser.js
  * src/adapters/mocha-blanket.js
  * src/qunit/reporter.js
And the follow-on dist/ updates...