feature: add support for cplus executor

[xcaspar]

Does this pull request fix one issue?

See #137 for details

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@e391c95). Click here to learn what that means.
The diff coverage is 1.2%.

@@            Coverage Diff            @@
##             master     #142   +/-   ##
=========================================
  Coverage          ?   14.85%           
=========================================
  Files             ?       56           
  Lines             ?     2781           
  Branches          ?        0           
=========================================
  Hits              ?      413           
  Misses            ?     2331           
  Partials          ?       37

Impacted Files	Coverage Δ
util/util.go	3.4% <0%> (ø)
cli/exp.go	0% <0%> (ø)
cli/revoke.go	0% <0%> (ø)
cli/main.go	0% <0%> (ø)
cli/prepare_jvm.go	24% <0%> (ø)
cli/prepare_cplus.go	0% <0%> (ø)
cli/prepare.go	34.14% <50%> (ø)

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