[l2h] dvips version detection + perl warning

[Fabrice Popineau]

> Conclusion: On windows it is currently a bad idea that the tools lies
> in directories which have spaces in their names.

Unfortunately, under windows, it is M$ required that programs be
installed in this location. One reason for this is permission policy :
the defaults attributes of this directory are different from the default
attributes of c:\. If you install in c:\Local, non privileged users may
not be allowed to use your software.

My workaround was to remove any absolute path from l2h (actually not
such a big deal). Just let l2h refer to "dvips.exe" instead of 
"c:\program files\texlive\bin\win32\dvips.exe" and that was enough.
On TeXLive 7, you can find a version of l2h tailored for texlive, ie a
version that you do not need to configure.

Fabrice