Add legend, legend_loc, and title params to charts

[mroberge]

Fixes #60, which @mopickel pointed out.

[codecov-io]

Codecov Report

Merging #61 into develop will increase coverage by 3.98%.
The diff coverage is 90%.

@@             Coverage Diff             @@
##           develop      #61      +/-   ##
===========================================
+ Coverage    82.74%   86.72%   +3.98%     
===========================================
  Files            8        8              
  Lines          562      565       +3     
  Branches       105      108       +3     
===========================================
+ Hits           465      490      +25     
+ Misses          65       48      -17     
+ Partials        32       27       -5

Impacted Files	Coverage Δ
hydrofunctions/charts.py	85.57% <90%> (+22.21%)	⬆️

---

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 bf1f296...9e3eb0c. Read the comment docs.