test_tinfer: Add checks for mutually referential types and value
conditionals (taken from if4.as)
Merge branch 'axllib-tests' into pab/tmp/testmerge
The form A: BT == add { local AAA: BT with == add; ...}
ie. nested adds with a category in both inner and outer adds was not
quite working - the "%%: BT" symbol was not present in the inner add,
and so picked up from the outer.. so you get a big kaboomy noise.

This also shows in bug1253 - outer definitions being picked up by 'add'.
genfoam.c: Don't generate (Seq (Cast (....)); it should always be
equivalent to .....
Make note in gf_prog.c that outer casts are not allowed.
tform.c: Add Category to things that can contain conditions.
libax0: Add a few tactical 'import from Boolean' where needed.  This avoids
an assertion failure.  Really ought to dig out the cause of Boolean not
being imported automagically, but not high priority.
Merge branch 'master' into pab/devel