Apply patch D8816, from Zachary(AFWS) for collection boolean operand.

Also added code so that exact solver does the whole collection at once.
This patch allows users to use a collection (as an alternative to Object)
for the boolean modifier operand, and therefore get rid of a long modifier stack.

Add a Self option to the Exact boolean modifier. Fixes T52425.

With this option, self-intersections in either or both operands
will be handled properly (if both sides are piecewise winding
number constant, and maybe some other cases too).
In the Boolean tool, this flag was there already but the code
forced a unary operation in that case; this commit corrects it
to make a binary operation. This flag makes the code slower, which
is why it is an option and not an always-on thing.

Fix T75827, boolean of non-manifold objects leaves stray edges.

Well, this only fixes the example if one uses the new Exact mode,
but since that is available, seems fair to call this fixed.
Since these were not closed-volume operands, the Exact mode needed
some adjustment to the threshold used for "inside-outside" tests
for the case of deciding if the cutter is inside the other shape
for a Difference.

New boolean: Fix second example in T79404.

The code to detect non-trivial coplanar intersection sometimes
falsely said there wasn't one. This caused some coplanar intersections
to be missed. Also added a test for this case.

New boolean: silence an "unused" warning.

Previous commit stopped using some functions. Since I may need
them again for future performance tuning, these are just ifdef'd out
for now.

New boolean: another performance improvement.

Instead of calculating exact normals for all faces, just do it
for those that potentially intersect. A big improvement for dense
meshes that only intersect in relatively few places.

Re-enable modifer and bmesh_boolean tests.

These were disabled in the newboolean merge commit.
This commit renables them, using the original 'FAST' solver
so that the result objects need not change.
A TODO to add more tests using the 'EXACT' solver,
though most functionality there is now covered by unit gtests.

New Boolean: performance improvement.

Avoided cost of searching for coplanar clusters in many cases.

New boolean: fixed a bug in coplanar intersect.

The code that found coplanar clusters was not updating a bounding box.
Also, code that was detecting non-trivial coplanar intersects was
slightly wrong, but that would not have caused any functional problems.

Change cmake configs for full and release to enable WITH_GMP.