Fixing load() in demos



Having added a few bug reports I'd like to fix one.  Many of the demos fail since they try load("foo.mc") or equivalent, but the file has been renamed foo.mac

I will fix these if we can agree on the fix.  Do we want:
 - load("foo.mac")
 - load(foo.mac)
 - load(foo)
 - load('foo)
 - load(FOO)
 - load('FOO)
 - or ....