Could you try the newly added build.sh script from the repository?
EDIT: Hm, it seems to run a lot slower on my machine when built through that script...
For now it remains a mystery to me as to why this is, but - if the same is true for you - it should run smoother if you build using QtCreator (sudo apt-get install qtcreator). The contents of the build script could help you achieve this.
