Added a test for the Bio-PEPA which uses the heaviside function. This uses both the H(a) syntax and the heaviside(a) syntax. The test is currently failing because of a parse error, which is the bug I created the test for. However it will also fail because the expected results are just Nones at the moment since I do not know what the correct results should be.
Added a test for the Bio-PEPA which uses the heaviside function. This uses both the H(a) syntax and the heaviside(a) syntax. The test is currently failing because of a parse error, which is the bug I created the test for. However it will also fail because the expected results are just Nones at the moment since I do not know what the correct results should be.

allanderek/pepapot,allanderek/pepapot,ageorgou/pepapot,ageorgou/pepapot