ENH: return axis when plotting QStatistic, default to equal aspect when plotting PointPattern

[martinfleis]

Minor enhancements of our plotting code in PointPattern and QStatistic.

QStatistic now returns the axis so you can do anything you want with it, e.g. add contextily basemap or any other layer.

PointPattern defaults to equal aspect since it is expected that in most cases, coordinates are projected. This does not skew the geography. When they are in lat lon, assuming plate carree should also be a better option than the default ratio. In any case, since you can get ax now, you can change it afterwards.

[codecov[bot]]

Codecov Report

Merging #116 (2312ba4) into main (de0470a) will increase coverage by 0.04%. Report is 1 commits behind head on main. The diff coverage is 33.33%.

@@            Coverage Diff             @@
##             main     #116      +/-   ##
==========================================
+ Coverage   52.56%   52.61%   +0.04%     
==========================================
  Files          12       12              
  Lines        1851     1855       +4     
  Branches      317      317              
==========================================
+ Hits          973      976       +3     
- Misses        821      822       +1     
  Partials       57       57              

Files Changed	Coverage Δ
pointpats/pointpattern.py	69.66% <0.00%> (-0.40%)	:arrow_down:
pointpats/quadrat_statistics.py	59.13% <0.00%> (ø)
pointpats/process.py	49.54% <100.00%> (+0.46%)	:arrow_up:
pointpats/window.py	72.00% <100.00%> (+2.43%)	:arrow_up: