Adding Makefile

[matthewhudson]

Transitioning away from NPM scripts in favor of a Makefile to handle basic tasks, including releases (finally)!

[codecov-io]

Codecov Report

Merging #162 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #162   +/-   ##
=======================================
  Coverage   71.91%   71.91%           
=======================================
  Files           1        1           
  Lines         146      146           
=======================================
  Hits          105      105           
  Misses         41       41

Impacted Files	Coverage Δ
src/index.js	71.91% <100%> (ø)	⬆️

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[coveralls]

Coverage remained the same at 63.889% when pulling bd7686b on update/makefile-builds into a62ff3d on master.