Added DPMA version display
Disabled pin=vm checkbox for dpma < 2.1
Added sanity check for firmware json
Merge pull request #10 in FREEPBX/digium_phones from ~SGRIEPENTROG/digium_phones:master to master

* commit '9f642ceb3840457020682805dd3aebd1ee4a79e3':
  Added sanity check for firmware json
  Disabled pin=vm checkbox for dpma < 2.1
  Added DPMA version display
Improved doxygen output
Updated changes section