Change how man pages are built (and where they are built to). Building man

Change how man pages are built (and where they are built to).  Building man
pages should now be more consistent across systems.

* arch/Makefile.inc: Build yasm_arch.7 at top level, and in dist_man_MANS
instead of man_MANS.  Include build rule for building using XMLTO if XMLTO
is available.
* yasm/Makefile.inc: Likewise (for yasm.1).
* Makefile.am: Change man_MANS to dist_man_MANS.  Remove general rules for
.xml.1 and .xml.7.  Add dist_man_MANS to MAINTAINERCLEANFILES.  Remove
man_MANS from BUILT_SOURCES, DISTCLEANFILES, and EXTRA_DIST.

svn path=/trunk/yasm/; revision=1189