Fixed Typo edfreader and improve edfwriter

[holgern]

No description provided.

[codecov]

Codecov Report

Merging #23 into master will increase coverage by 0.04%.
The diff coverage is 80%.

@@            Coverage Diff             @@
##           master      #23      +/-   ##
==========================================
+ Coverage   58.36%   58.41%   +0.04%     
==========================================
  Files           6        6              
  Lines        3442     3446       +4     
  Branches      995      995              
==========================================
+ Hits         2009     2013       +4     
  Misses       1400     1400              
  Partials       33       33

Impacted Files	Coverage Δ
pyedflib/edfreader.py	68.07% <100%> (+0.6%)	⬆️
pyedflib/edfwriter.py	75.09% <75%> (-0.01%)	⬇️

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