Complete tests suites

[Kolaru]

While testing #114 I noticed that a problem was caught in the wrong test suite, namely NaN return value rather than Out of domain, because the latter does not test multidimensional function. This made me realize that several test suites are incomplete.

So I open this issue to list missing tests. I'll add them in a future PR.

Currently the todo list is:

• Add multi dimensional tests to the Out of domain suite.
• Add multi dimensional tests to the Infinite domain suite.
• Add one dimensional tests to the NaN return value suite.
• Use test in test/bisection.jl.
• Adapt tests in test/findroots.jl to the roots suite.
• Add tests in test/newton1d.jl to the tests for the 1D roots suite.
• Test that the examples in the example folder run without error.
• Add some tests from the sources given in docs/test_suites.md.
• Test function with interval parameter (cf. Krawczyk fails for functions with interval parameters #99).
• Add the convoluted double reciprocal case from Reciprocal of reciprocal misses root #131.

Please let me know here if other test suites need to be completed.