Added correct scalar conversion to bool (ie != 0). This means that loading images in to Image<bool> generally does the correct thing, with nonzero elements set to 1.
Added correct scalar conversion to bool (ie != 0). This means that loading
images in to Image<bool> generally does the correct thing, with nonzero
elements set to 1.

Also, marked some FIXMEs in the scalar convert code. I think that the byte
to float conversion is not fully correct.

oneminot/libcvd,oneminot/libcvd,oneminot/libcvd