tests: skip tests if maxima not available

See merge request !19

Implement a LaTeX mapper

See merge request !18

Fix, test order of operations in shift stringification (closes #6 on gitlab)

Closes #6

See merge request !17

[bugfix] Correct mod implementation for right operand being 1

See merge request !16

In fact x % 1 is 0, not x.

Un-pickling of `CallWithKwargs`.

See merge request !15

Fixes/improvements to get_dot_dependency_graph().

See merge request !14

- Fix a typo in an argument name.
- Reverse the dependency edges, because it's more typical for the
  arrow to point to the instruction that the computation depends on,
  rather than the other way around.
- Add a hook for customizing node attributes.