Merged some simplified constraints from another branch.
Removed superflous constraints.
(cherry picked from commit 37b59a68f6d9b796a03f5985af234d68ccb8de31)

Conflicts:

	src/Diagrams/TwoD/Size.hs
Removed some more constraints.
(cherry picked from commit d165adb6188062c809dba4aca167a7728744b199)

Conflicts:

	src/Diagrams/TwoD/Arc.hs
Cherry picked some edits from: 724352b94b70a533c8de85b88c219ef51dadb618
Tried to simplify the constraints.

Did not really get simpler, got rid of some 'a ~ Scalar'.
(cherry picked from commit c2c8cb97635cc41f97a69216743a6e6b869d0c7c)

Conflicts:

	src/Diagrams/TwoD/Arc.hs
Tried to remove as many constraints as possible.

Still 'a ~ Scalar (V (P2 a))' needs to remains, because of
the 'orient' function.
(cherry picked from commit c46190f0f2e1b16877276495f33a67ae3a0eaa93)
Reified constraints.
(cherry picked from commit 40a443346ee761588fbb8e697ac01c969ccee724)
Generalized booleans, simplified constraints and used the new angle helpers.
(cherry picked from commit d8920bfd95187daf39c09845e985891fb9151ab0)

Conflicts:

	src/Diagrams/TwoD/Transform.hs