Reduce flash memory consumption

The previous software is using too much flash memory. Several measures are taken in V2 R1 to reduce the flash memory consumption in the phones. These measure are neither seen from the user nor from the administrator. There is one exception (as always) to this rule.

The built in polyphonic ringer files are substituted by MIDI files. The sound of the ringer tones is very similar to the polyphonic ringer tones, but the difference may be recognized by the user.