Fixed private messages when sent from multiple clients

[insomniacslk]

And also refactored a bit and removed dead code

[codecov]

Codecov Report

Merging #23 into master will decrease coverage by 0.26%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master     #23      +/-   ##
=========================================
- Coverage    3.78%   3.51%   -0.27%     
=========================================
  Files           6       6              
  Lines         423     455      +32     
=========================================
  Hits           16      16              
- Misses        407     439      +32

Impacted Files	Coverage Δ
irc_server.go	0% <0%> (ø)	⬆️
event_handler.go	0% <0%> (ø)	⬆️
irc_context.go	0% <0%> (ø)	⬆️

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