WIDGPT-53: Resized icons to same height; added text background

Resize icons to be the same height, image icons responsive

After picture
![app_tiles](https://cloud.githubusercontent.com/assets/3999821/4328733/97803846-3f8a-11e4-85da-7fb27b727cae.png)

Why add class="app-launcher-item?"  The additional CSS selectors that use it look (potentially) unsafe for life on the portal page.  (i.e. different publications of the portlet, based on configuration, may generate different CSS... but these selectors aren't namespaced.)