Added cross platform compatible script for finding hwloc library.
Added support to FindHwloc.cmake for Hwloc_CFLAGS and Hwloc_LDFLAGS

Now script also creates Hwloc_CFLAGS and Hwloc_LDFLAGS variables where include and library directories are already in compiler switch format instead of cmake lists.
Fixed setting Hwloc include directories as list instead of string to prevent error with empty list.