🆙 Bump up 0.4.2

Merge pull request #152 from mattak/fix/statejson_extension

StateJsonEditor should ignore package.json #150

Merge pull request #149 from mattak/feat/upm_doc

Update upm install instructions

2018-10-13: fix for .net 4.0 runtime

2017-10-30 optimize state editor

2017-10-11 clone performance improved

2017-09-06 state editor created

2017-06-27: update for new features

2017-01-10: show reducer warning and add todo example

2016-12-24: UniRx, Ducks style