Merge pull request #9 from jkangas/master

Request for pulling radio access tech preference query to main branch
Merge pull request #10 from jkangas/master

Request for pulling prefeffed network type selection to main branch
Merge pull request #11 from jkangas/master

Request for enabling phonebook implementation main in branch
[rilmodem][WIP] Create and split conference calls
[rilmodem][WIP] Hold, resume, swap calls

Signed-off-by: Martti Piirainen <martti.piirainen@tieto.com>
Merge pull request #12 from marttipiirainen/master

Enabled conference calls, and hold/resume