version bumped to 0.3.22

kotlin updated to 1.3.11, gson -> 2.8.5

removed deepCopyUtils and use directly deepCopy that is available fro…

…m gson 2.8.2

kotlin bumped to 1.2.10
version set to 0.3.20

kotlin bumped to 1.2.0, gson to 2.8.2

updated readme