rilmodem: Fix for memory leaks
gril: Add RIL voice call parcels handling

Functions for packing/parsing RIL requests, replies, and unsolicited
events, for voice call related cases.
rilmodem: Re-factor voicecall code

Re-factor code to ease unit testing and OEM adaptation if needed.
unit: Add tests for gril voicecall functions
Merge pull request #28 from alfonsosanchezbeato/voicecall-refactor

Voicecall refactor
Merge pull request #30 from alfonsosanchezbeato/fix-leaks

rilmodem: Fix for memory leaks
rilmodem: Parse reply to check for file not found
gril: Fix ril_msg invalid event_data bug

Wrong event data instead of nothing was being passed to upper layers
when the parcel had no event data (LP #1254219).
gril: Add functions for call-volume refactor

Functions for creating requests and parsing replies needed by
rilmodem call-volume module.
rilmodem: Re-factor call-volume

grilrequest and grilreply functions are used now for creating and
parsing parcels.
unit: call-volume parcels tests
Merge pull request #29 from alfonsosanchezbeato/sim-no-file

Remove ofono_error messages for not found files
Merge pull request #33 from alfonsosanchezbeato/callvolume-refactor

Callvolume refactor