Correct html errors in Math #2

The blocks for RegNonZeroPower and PowerLinearized contained wrong html in
the documentation, to which the unit tests gave errors. This is
corrected.
Add unit tests for Average and Polynominal #2
Add unit test for trapezoidalIntegration #2
Update unit test TrapezoidalIntegration #2
Add unit test for isMonotonic #2
Update unit test for IsMonotonic #2

The unit test includes only Booleans. Therefore, plotting results is not
straightforward. This version plots one of the test functions, which is
not ideal.
Modified Unit test for TrapezoidalIntegration

Now the unit test plots the result of the function call
trapezoidalIntegration