* Add `engine` crate

* Add `env_types` crate

* Adapt `env`, `lang` and `storage`

* Adapt examples

* Adapt CI

* Symlink license and readme

* Throw `TypedEncoded` out of `engine`

* Improve Erc20

* Bump versions to rc3

* Fix clippy error: Manual implementation of `Option::map` (#717)

* Implement comments

* Fix yml

* Improve structure

* Add tests

* Fix function signature

* Get rid of `engine`s singleton

* Revert instantiate stuff

* Implement review comments

* Make `Storage` non-generic

* Improve API for emmitted events

* Migrate to `panic_any`

* Clean up import

* Import `panic_any`

* Implement comments

* Fix param

* Use type

* Store balances in chain storage

* Fix tests

* Use individual storage per contract

* Implement comments