better visualization of labeled multi-qubit circuits

[GiggleLiu]

TODO:

• annotate legs (not needed anymore)
• smaller graph size, make scale and graphsize work properly
• apply scale on font size
• do not convert FSim to basic types?
• phase gate should be a dot
• move lines to front

[codecov]

Codecov Report

Merging #55 (f701d01) into master (f553a60) will increase coverage by 8.49%.
The diff coverage is 80.85%.

@@            Coverage Diff             @@
##           master      #55      +/-   ##
==========================================
+ Coverage   50.75%   59.25%   +8.49%     
==========================================
  Files           4        4              
  Lines         329      378      +49     
==========================================
+ Hits          167      224      +57     
+ Misses        162      154       -8     

Impacted Files	Coverage Δ
src/vizcircuit.jl	78.63% <80.64%> (+11.38%)	⬆️
src/helperblock.jl	93.33% <100.00%> (-6.67%)	⬇️

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