Embedding drawing node size

[joseppinilla]

The overlapped_embedding option is hogging the node_size parameter.
This PR allows the user to control it again, if wanted.

[codecov-io]

Codecov Report

Merging #158 into master will increase coverage by 0.02%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #158      +/-   ##
==========================================
+ Coverage   71.89%   71.92%   +0.02%     
==========================================
  Files          26       26              
  Lines        1637     1635       -2     
==========================================
- Hits         1177     1176       -1     
+ Misses        460      459       -1

Impacted Files	Coverage Δ
dwave_networkx/drawing/qubit_layout.py	8.13% <0%> (+0.06%)	⬆️
dwave_networkx/algorithms/elimination_ordering.py	86.59% <0%> (-0.35%)	⬇️

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[arcondello]

Looks good! Thanks!

[arcondello]

@joseppinilla , do you need a new dnx deploy or are you ok installing from master for now?

[joseppinilla]

Installing from master should be OK for now.
Thanks!