pjsip: updated bundled version to revision 4699

Ignore-this: af5d9ac91638f8363a2b455767775359

WebRTC AEC and OPUS codec makefiles where adapted to
changes in PJSIP build system.

coreaudio_dev.c is no more, so our customizations where
merged in the new coreaudio_dev.m

darcs-hash:20131227105643-56b4d-214d50fa82f73e488cc0828e8e508265a6f52036
Raised core revision

Ignore-this: 5709ecb8aca249cb5fec1a71c9c229a0

darcs-hash:20131227113943-56b4d-513721601057719374f28b132f2aa3f22ad3ff50