Handle out-of-bounds coordinates during evaluation

[Sichao25]

Handle out-of-bounds cases by throwing an exception or filling a given value. CLAMP mode (map to nearest elements) is not yet implemented.

[jacobmerson]

@hgangwar please review this when you get a chance. Changes here are what we discussed about handling points outside the domain.

[hgangwar]

@jacobmerson , the test case validates exactly the functionality we need. As I understand it, any out of bounds vertex's element index is marked as something < 0, and handled accordingly via OutOfBoundsMode. I will verify it further with the convergence testcase.