Expose GraphvizFormatting and test in python

[senselessDev]

This exposes the GraphvizFormatting class with direct member access as discussed in #1053. This allows to do some configuration on the saveGraph call that was not possible via the bindings before.

It also adds a few basic tests for it.

Lastly, I had the problem that the python-test target was only testing the files that were copied to the build directory before but not any new tests. Adding the dependency fixed that by always copying the tests. I don't know if that is wanted behavior.

[dellaert]

This is awesome! I'll trigger CI so please wait on the results before pushing, so CI only has to run once more if any problems pop up there.

[senselessDev]

Thanks for your positive feedback!

One additional thing I just noticed: in the readme of the python directory it is written it should take CMAKE_INSTALL_PREFIX into account. But according to my observation, it does not. I think we have to add --prefix ${CMAKE_INSTALL_PREFIX} to the setup.py install line in the CMakeLists.txt.

Edit: Obviously, I can push that if you say we want that and the CI is done ;)

[dellaert]

Thanks for your positive feedback!

One additional thing I just noticed: in the readme of the python directory it is written it should take CMAKE_INSTALL_PREFIX into account. But according to my observation, it does not. I think we have to add --prefix ${CMAKE_INSTALL_PREFIX} to the setup.py install line in the CMakeLists.txt.

Edit: Obviously, I can push that if you say we want that and the CI is done ;)

@varunagrawal comment?
The comment might be out of date because as far as I know, we now use the default python install locations, which I think is probably appropriate.

[senselessDev]

I actually like the option to install it somewhere else. By default, it wants to install to /usr/local which requires root privileges. When you specify CMAKE_INSTALL_PREFIX to ~/.local for example, it usually is also on PATH/PYTHON_PATH and only a per-user installation which does not require root privileges.

[varunagrawal]

I need to check but that part of the readme may indeed be out of date.

[senselessDev]

Changed copyright section and included --prefix option for setup.py. I think the second point only is beneficial and has no drawbacks.

[dellaert]

Sorry, but the prefix thing has to be a different PR. We can't risk unintended consequences. Please remove from this PR, but we'd love it if you could submit as a separate PR and explain the behavior. I don;t understand well enough what it does.

[dellaert]

Thanks !!!!!