PJSIP 2.1

This is a fork of the 2.1 release of PJSIP. This fork pulls in the libsrtp code from the feature-openssl branch, which provides support for AES-NI. This fork also adds support for AES 192/256 and AES-GCM mode.

When building this code, the build host requires the OpenSSL 1.0.1 devel package to be installed. Other than this new dependency, the build procedure has not changed:

./configure
make dep
make