Add CameraGphoto2 to existing crappy available cameras

[jeffwitz]

This is a pull request for the implementation of the DSLR cameras.
It uses the gphoto2 library in order to capture images

[WeisLeDocto]

To make your new Camera object appear in the documentation, you'll need to add it at two separate places in the documentation source files:

• In the docs/source/crappy_docs/cameras.rst file (see the other cameras for the syntax)
• In the docs/source/features.rst file, where a brief description will be needed (again check the syntax for the other Camera objects)

You can check locally that the documentation builds as expected, by installing sphinx, as well as the other dependencies listed in docs/source/requirements.txt, and calling the make html directive on the docs/Makefile.
Alternatively, the documentation is automatically built when you push to this pull request, see for example the build for your last commit. This way you can know if anything went wrong.

[jeffwitz]

I add everything, Do I need to redo, or do you see the changes ?

[WeisLeDocto]

The documentation couldn't build after your modifications, see the build log for details.

[WeisLeDocto]

I made some substantial changes to your code. It contained several lines that needed to be fixed, the overall style and layout could be improved, and the documentation as well. I've been picky as this code for now goes into crappy, I'll surely be less strict for code going directly to crappy.collection once it's implemented.

Can you please double-check that the code still works as expected on one of your cameras ? Once this is confirmed, or the necessary fixes are brought, I can merge this PR.

[jeffwitz]

I made some substantial changes to your code. It contained several lines that needed to be fixed, the overall style and layout could be improved, and the documentation as well. I've been picky as this code for now goes into crappy, I'll surely be less strict for code going directly to crappy.collection once it's implemented.

Can you please double-check that the code still works as expected on one of your cameras ? Once this is confirmed, or the necessary fixes are brought, I can merge this PR.

Thanks @WeisLeDocto , I will look at it tomrrow

[WeisLeDocto]

Thanks @WeisLeDocto , I will look at it tomrrow

@jeffwitz could you check if the code works as expected ? So that I can merge this PR.

Thanks