Added cuda run test to build system so that configure doesn't erroneously report cuda as working on systems that provide the tools to compile and link cuda code but do not provide the dynamically linked libraries to cuda binaries.
Changed build system so that it leaves out the libraries cudart and cufft if the cuda checks failed. Properly fenced all the code depending on those libraries. Unfortunately the fences don't work because the precompiler constant CUDA gets set even when the checks fail.
Configure script now only defines the symbol CUDA if all checks for cuda, including the run check, succeed. Since in that case, the cuda libraries are left out and all cuda code is fenced off, this should produce a working ESPResSo binary even on system where the cuda build tools are properly set up but the dynamic libraries are not properly referenced.
Extensively tested build system with respect to different proper and broken cuda setups. Found and fixed two more bugs, one in the code fences and one in the cuda indicator for the makefile.
Added location information of cuda headers also to CC, so that header files which contain declarations referencing cuda datatypes can also be processed by compilers other than nvcc.
Merge branch 'cuda_autodetect' of git://github.com/rempferg/espresso into cuda-autodetect
Fixed CUDA autodetection.