Add gtest headers and libraries

Add gtest headers and libraries to cards/unittest/{include,lib}. These
two directories are obtained in the following procedure. {bin and share}
folder should be useless to us, so remove them.

$ cd cards/thirdparty/gtest
$ ./configure --prefix=/home/phye/ws/cards/unittest
$ make
$ make install
$ cd /home/phye/ws/cards/unittest
$ rm -rf bin share