Added pdb_selb to filter by B-factor values

[ahmedselim2017]

Hi,

I was working on some Alphafold predictions and needed a tool to filter with B-factor and saw #163. So I have written a script called pdb_selb to filter atoms by their B-factor values.

However, as the signs < and > may interfere with shell redirect commands, I have added an option to select the operator that should be used instead of directly writing the operation and the threshold value as the same option.

Also, I have added tests and documentation for pdp_selb. But, as this is my first time contributing to this project please let me know if you have any feedback or improvement ideas!

[joaomcteixeira]

Hi @ahmedselim2017 !

Thanks for your contribution. I like the way to presented the PR, everything follows the pdb-tools strategy and architecture. I left some comments I think you should address.

@amjjbonvin @JoaoRodrigues The new tool here follows the pdb-tools "one script one job" paradigm and is something we don't have yet. Personally, I like it. Once the comments are addressed I agree with merging it. It should be [FEATURE].

Cheers,

[joaomcteixeira]

I am not sure if you can directly claim the whole copy right for this script has many of the sections are copied or based on the original pdb-tools project. For clarity and fairness, I suggest stating that the copyright if both from the pdb-tools project and yours.

opinon @JoaoRodrigues ?

[ahmedselim2017]

Of course! Since most scripts in the repository usually have only one author listed, I hadn't thought about that. Also, should I update the __author__ and __email__ parts as well, or only the copyright part?