Added note about running 'autoreconf' if building from GitHub.
Clarified that --with-spir requires installation path, not build path.
cl_device_id object intialised at same time as platform.
Added conflicting work-group ID to data-race output.
Merge pull request #57 from silverclaw/master

Some more half support
Fixed union assignment for CL_DEVICE_GLOBAL_MEM_[CACHE_]SIZE.
User-include syntax for non-system headers.
Fixed argument type introspection in oclgrind-kernel.