WFS Layer Selection UI Improvements

This pull request enhances the WFS layer selection UI to:

* Improves the row and column sizing for the item list
* Allow filtering type name by keywords
* Using the type name title for the layer name when add to the map

The main driver for this enhancement is usability of the LINZ Data Service (http://data.linz.govt.nz) which has over 800 layers in it's WFS service. Also to make typeName names unique the service uses ID identifiers, and "titles" for the actual layer name.

See attached screenshot for the proposed changes.

![wfs_ui_improvements](https://f.cloud.github.com/assets/580022/326695/8b68e60e-9b42-11e2-9869-0598d866ef68.png)