Significant improvements to digium_phones module prior to DPMA 2.1 release

Cleaned up functions.inc, moved extra classes to classes subdir, config generators to conf subdir
Added pin=voicemail support for DPMA 2.1
Logo improvements: upload most any image format, automatically resized, D45 now supported
Status (presence) will now use FreePBX PreseneceState module settings if it is enabled
Can now download older firmware versions, not just the current one
Ringtones can now be configured individually to the phone without having to be set as default
General status page now shows version of the DPMA module installed in Asterisk

Requesting version 2.11.2.0 to be initially a beta release.