[RILMODEM] refactor gprs driver

Signed-off-by: Jarko Poutiainen <Jarko.Poutiainen@oss.tieto.com>
[RILMODEM] refactor gprs-context driver

Signed-off-by: Jarko Poutiainen <Jarko.Poutiainen@oss.tieto.com>
[RILMODEM] code review and checkpatch cleaning

Signed-off-by: Jarko Poutiainen <Jarko.Poutiainen@oss.tieto.com>
[RILMODEM] code review and checkpatch cleaning

Signed-off-by: Jarko Poutiainen <Jarko.Poutiainen@oss.tieto.com>
[RILMODEM] fake also roaming

Signed-off-by: Jarko Poutiainen <Jarko.Poutiainen@oss.tieto.com>
Merge pull request #228 from jpoutiai/master

Refactoring rilmodem gprs implementation
[test] Add test script for explicit call transfer
[rilmodem] Explicit call transfer driver implementation
Merge pull request #229 from mkuukkane/transfer

Explicit call transfer rilmodem implementation
[voicecall] Cancel pending DTMF tones before hanging up call.
Merge pull request #230 from martinjones/master

[voicecall] Cancel pending DTMF tones before hanging up call.