Temporary independent repo for tests of the legacy mongo-cxx-driver repo

This repo pulls down GTest and the independent mongo "legacy" driver and builds them then builds and runs unit tests against the built driver.

Written in CMake for expediency due to awesome power of ExternalProject_add.

Instructions:

git clone git@github.com:acmorrow/mongo-cxx-driver-test.git
cd mongo-cxx-driver-test
mkdir build
cd build
cmake ..
make all test