Change resolution when resizing window

[astrofrog]

This is a WIP. Remaining to-dos:

• [x] Figure out how to avoid segfault on MacOS X backend: https://github.com/matplotlib/matplotlib/issues/9655
• [x] Only set up this behavior for an interactive backend

[coveralls]

Coverage decreased (-2.02%) to 97.98% when pulling 715512746f8d24b6866bdd2b015934dedee4da87 on resize-downsample into 79083ae1fd3bacccb215e40f067fb263c37614a6 on master.

[coveralls]

Coverage decreased (-2.02%) to 97.98% when pulling 715512746f8d24b6866bdd2b015934dedee4da87 on resize-downsample into 79083ae1fd3bacccb215e40f067fb263c37614a6 on master.

[astrofrog]

I've now changed this so it will only work for Qt by default, and we can add more backends explicitly once we check that they work.

[codecov-io]

Codecov Report

Merging #14 into master will decrease coverage by 1.07%. The diff coverage is 84.37%.

@@            Coverage Diff             @@
##           master      #14      +/-   ##
==========================================
- Coverage   99.29%   98.21%   -1.08%     
==========================================
  Files           9        9              
  Lines         426      449      +23     
==========================================
+ Hits          423      441      +18     
- Misses          3        8       +5

Impacted Files	Coverage Δ
mpl_scatter_density/scatter_density_artist.py	95.23% <100%> (+0.23%)	:arrow_up:
mpl_scatter_density/generic_density_artist.py	94.3% <81.48%> (-3.72%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update c447ca4...5112197. Read the comment docs.