Add Write Request operation in gatttool
Add Write Request operation in gatttool

Add option and callbacks for Write Request operation in gatttool.

silent-snowman/bluez,silent-snowman/bluez,silent-snowman/bluez,ComputeCycles/bluez,ComputeCycles/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,mapfau/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,pkarasev3/bluez,pkarasev3/bluez,mapfau/bluez