automatic minmax limits

[lukashergt]

Automatically set all limits not specified by a .ranges file to their respective minimum and maximum values in the sample.

Fixes #36

Checklist:

• I have performed a self-review of my own code
• My code is PEP8 compliant (flake8 anesthetic tests)
• My code contains compliant docstrings (pydocstyle --convention=numpy anesthetic)
• New and existing unit tests pass locally with my changes (python -m pytest)
• I have added tests that prove my fix is effective or that my feature works

[codecov]

Codecov Report

Merging #80 into master will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #80      +/-   ##
==========================================
+ Coverage   91.15%   91.19%   +0.03%     
==========================================
  Files          15       15              
  Lines        1323     1329       +6     
==========================================
+ Hits         1206     1212       +6     
  Misses        117      117              

Impacted Files	Coverage Δ
anesthetic/samples.py	98.38% <100.00%> (+0.03%)	⬆️

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[williamjameshandley]

This looks great. I've had a quick look and it seems like it works well. Could you iterate the version number in the README to 1.2.6 to signify a change, and I'll formalise this as a new release.

[lukashergt]

I noticed one thing:
In the current setup, it doesn't assign limits to logL or weight. Would we prefer to have limits set on them, too? That might be better for cases where a PC run is ended prematurely and logL will have a sharp cutoff which could get washed out by the KDE without limits.

[williamjameshandley]

I think it makes sense to automate this too. It would be harder to communicate in the case that you don't want a hard limit, but you could always do that manually at the python level if you had to. You should probably also do this for the nlive column as well.

[williamjameshandley]

This looks great. Please squash and merge!