cmake build system

Initial cmake-based build system.

Tested on Ubuntu 14.04.

Partial list of packages which need to be installed:
```sh
sudo apt-get install pyqt5-dev
sudo apt-get install git-svn
sudo apt-get install freeglut3-dev
sudo apt-get install libcurl4-openssl-dev
sudo apt-get install qt5-qmake
sudo apt-get install libqt5opengl5-dev
sudo apt-get install libqt5help5
sudo apt-get install qttools5-dev
sudo apt-get install python3-pyqt5
sudo apt-get install libxmu-dev libxi-dev
sudo apt-get install qttools5-dev-tools
sudo apt-get install qt5-default
```

Then, run
```sh
mkdir build
cd cmake ..
make
cd ..
./knossos
```