Change mechanism for generating a temporary cdxj file.

[machawk1]

Closes #696

[codecov]

Codecov Report

Merging #697 into master will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #697      +/-   ##
==========================================
- Coverage   29.26%   29.23%   -0.03%     
==========================================
  Files          10       10              
  Lines        1244     1245       +1     
  Branches      184      184              
==========================================
  Hits          364      364              
- Misses        857      858       +1     
  Partials       23       23              

Impacted Files	Coverage Δ
ipwb/__main__.py	0.00% <0.00%> (ø)

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[ibnesayeed]

LGTM!