paper button template updated with raised

Polymer 0.4.2 introduced breaking changes to <paper-button>; the raisedButton attribute has been changed to raised.  As it is, generated web apps will not properly display the button.

Label is also deprecated, to wit: "label attribute is now deprecated. The new usage is to put the label in light DOM."

The raisedButton => raised attribute change also needs to be propagated through the rest of the templates as well, i.e., the chrome app polymer template, etc.
Merge pull request #3608 from m4b/patch-1

paper button template updated with raised