ipe 7.1.6

Version bump, Modernisation of syntax, removes the patch in favour of flags to reflect recent upstream changes, patches the shared objects into dylibs.
Yeah, me too, to be honest. If I hadn't already poured hours of work into the darn thing between the last update and this one I'd be pretty tempted to boneyard it already. Don't love supporting things that upstream aren't interested in supporting on x platform.