updated autoconf/automake files to incorporate the IXML_HAVE_SCRIPTSUPPORT setting

Changes;

1. Previously scriptsupport only worked in Visual Studio, this makes it work on the other platforms as well though autoconf/automake
1. Changed the default from excluding scriptsupport to default including it. Because it adds a field to the ixml-node structure. Accidentally having a field that you do not use is safer than accidentally accessing a field that isn't there.
1. renamed `SCRIPTSUPPORT` to `IXML_HAVE_SCRIPTSUPPORT` for consistency
1. reverted the previously exported uuid functions