Added further Effects handling from Showdown parsing and fainting

[caymansimpson]

We add three things:

1. Parsing of -singlemove (showdown protocol and -singleturn (showdown protocol)
2. Effect Handling for when a pokemon faints (we should remove all effects since they are no longer relevant to the battle state)
3. Tests for these

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.40%. Comparing base (f458350) to head (c48ce66).
Report is 69 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #596      +/-   ##
==========================================
+ Coverage   83.38%   85.40%   +2.02%     
==========================================
  Files          39       42       +3     
  Lines        3918     4303     +385     
==========================================
+ Hits         3267     3675     +408     
+ Misses        651      628      -23