use / for MSWin32 paths

Windows accepts \ or / as path separators, and uses \ as the "default"
(this File::Spec uses it as its default).  This is problematic for
shell commands as \ gets confused as an escape charater at various levels.
use / for MSWin32 paths (in test)
do not attempt to dl_load static libraries
Merge pull request #64 from plicease/mswin32_paths

Mswin32 paths