Addig simple pubic domain domain QR Code class to main libs, initially
using it to add 'display as QR code' to field element
First cut at adding "Display as QR Code" to field element.  Working in
list view, just need to add it to detail view (but had to get this
commit done so I could pull and merge another change)
Merge branch 'joomla3' of github.com:Fabrik/fabrik into joomla3
Added QR code rendering for field element in detail view.