James Bigler authored Mar 26, 2015 and Brad King committed Apr 09, 2015

A previously undocumented feature allowed overriding the format
specified to CUDA_WRAP_SRCS with a source file property called
CUDA_SOURCE_PROPERTY_FORMAT.  I added documentation for this feature as
well as added the ability to let nvcc compile any file regardless of
type if this property was found.

In addition, I also fixed a couple of bugs with the calls to
_cuda_get_important_host_flags that weren't garding the arguments with
"" to prevent empty values from causing errors.