Add CDMA and multimode support to reference-ril

Reference RIL will query emulator modem the supported radio technologies
and the current radio technology and respond to telephony with the
information. Support for basic CDMA RIL request messages and messages
to set and query preferred network mode to be able to switch between
radio technologies.

Change-Id: I950d36691f3e4029f42efe265dc1bb0016b0f410