Remove handlers for ufl.Constant and friends.
Update reference data pointer to be486f27acd932cae32243024f418b0ca12f9c66.
Rename ._uflclass -> ._ufl_class_ for consistency with new type traits.
Update reference data pointer to a32c4a891e800e22f23877b8bd966eea15b1cee1.
Replace .operands() with .ufl_operands everywhere.
Remove unused handlers.
Update reference data pointer to 9cc32a7ba7a17850d99dac13f3a45deb195afb02.
Update reference data pointer to 2f2479fc05cce6ee45d61203d837e19ca5b415ee.
Merge branch 'martinal/topic-ufl-core-redesign' into martinal/topic-ufl-core-redesign-rebase

Conflicts:
	ffc/quadrature/quadraturetransformerbase.py
	test/regression/ffc-reference-data-id
Update reference data pointer to 2ba9e0863c8a3b8505704f6f4eb990b3f61e2329.
Import fix.
Expand prefix to be absolute path when installing.

Fixes problem with UFC CMake files.
Move debug import.
Merge branch 'garth/fix-prefix-relative-path'