Working branch

This introduces the three point coupling for the GPU, allows the use of flat, Gaussian, or "cut Gaussian" noise, both of which are documented in the User's guide. Importantly the default noise in the LB is now FLAT, whereas it used to be GAUSS, and perhaps an email should be sent to the User's Mailing List (though when the reverse switch was made this wasn't done). Furthermore these commits fix the bug in the FLAT noise in the LB GPU version, a bunch of warning, an issue with running make check on more than 8 processors, and some small issues in the test cases.