add function to get IP representation of subnet mask

[drahnieR]

No description provided.

[codecov-io]

Codecov Report

Merging #95 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #95   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          10     10           
  Lines         623    626    +3     
  Branches       94     94           
=====================================
+ Hits          623    626    +3

Impacted Files	Coverage Δ
lib/ipv4.js	100% <100%> (ø)	⬆️

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[beaugunderson]

@drahnieR thanks, this is a helpful addition--do you mind adding some tests in test/functionality-v4-test.js?

additionally, we should probably return .correctForm() instead of .address

[drahnieR]

Ok, that was a wired failure, but I think i've got the Travis build passed.