Add axis invert support

[AviSarmani]

No description provided.

[codecov-commenter]

Codecov Report

Merging #174 (f4ffc39) into master (4aa4d24) will decrease coverage by 0.09%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##            master     #174      +/-   ##
===========================================
- Coverage   100.00%   99.90%   -0.10%     
===========================================
  Files           33       33              
  Lines         1089     1091       +2     
===========================================
+ Hits          1089     1090       +1     
- Misses           0        1       +1     

Impacted Files	Coverage Δ
graphviz/backend/piping.py	100.00% <ø> (ø)
graphviz/backend/rendering.py	100.00% <ø> (ø)
graphviz/piping.py	100.00% <ø> (ø)
graphviz/rendering.py	100.00% <ø> (ø)
graphviz/backend/dot_command.py	95.45% <50.00%> (-4.55%)	⬇️

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