tsirlucas and jeffposnick Fix empty object when adding runtimeCaching custom plugins with workb…
…ox-webpack-plugin (#1598)

* fix empty object on custom plugins

* strip comments when parsing custom plugins

* use regex instead of strip-comments lib

* add test cases for custom plugins

* check if function content remains on custom plugin tests

* fix misshandled strings with //  on runtime-caching-converter

* add test case to misshandled // on runtime-caching-converter

* fix identation on runtime-caching-converter changes
Latest commit ea88b68 Aug 9, 2018