htmlprocessor.js - comma-separated targets, strip unparsed comment blocks

You can now pass comment blocks of the form: `<!-- build:<type>[:targets] [value] -->` where targets is a comma-separated list of targets, e.g. `<!-- build:<type>:dist,dev [value] -->`

If you pass `option.strip === true`, comment blocks will be removed (and their internal content remain) if the type doesn't exist or target doesn't match

----

Example

````javascript
	  processhtml : {
		  options : {
			  commentMarker : 'process',
			  stripUnparsed : true
		  },
		  one : {
			  files : {
				  'one.html': 'index.html'
			  }
		  },
		  two : {
			  files : {
				  'two.html': 'index.html'
			  }
		  }
	  }
````

````html
<script src="scripts/app.js"></script>
<!-- process:remove:one,two -->
<script src="scripts/modules/waitForAuth.js"></script>
<!-- /process -->
<!-- process:remove:two -->
<script src="scripts/services/user.js"></script>
<script src="scripts/services/auth.js"></script>
<script src="scripts/services/firebaseRef.js"></script>
<!-- /process -->
````

one.html becomes:
````html
<script src="scripts/app.js"></script>
<script src="scripts/services/user.js"></script>
<script src="scripts/services/auth.js"></script>
<script src="scripts/services/firebaseRef.js"></script>
````

two.html becomes: 
````html
<script src="scripts/app.js"></script>
````