ALLJOYN-2257: Fix ICE=off for Android

Add ANDROID_PROXIMITY to global environment when building for Android to inform
the Android framework code whether to include the proximity code.

Change-Id: Idac1476f31f8b03f74ed32ecf9a878b296194f2c
ALLJOYN-2306: Default ICE to 'off' for platforms that don't have proximity support.

Change-Id: I1db8f451655616fcfaa0c171e8c5889dab3b21fc
ALLJOYN-2266: Move Rendezvous server SSL certificates to ICE code.

Rendezvous server SSL certificates are specific to the ICE transport so those
certs should be there.

Change-Id: I02392b4393b8ea56c4c2e133f6f0679d62314aa8
ALLJOYN-2314: Fix OpenWrt build issue for services

Properly handle the 'cpp' binding so that services will be built within the
OpenWrt build framework.

Change-Id: Ide05578f272f04a2b4851bb3ffca94a9fafe78d7
ALLJOYN-2312 Implement a new Daemon Transport to support AllJoyn thin clients
connecting to the daemon over UART using the Serial Line AllJoyn Protocol(SLAP) protocol.