priority: immediate

* move schema.rs to darkfi/example
        * rename it to dao.rs
        * we want to be able to run it like how we run example/tx.rs
        * cargo run --example dao
        * and it should compile and work

priority: low

* the things in util.rs are not all utils
        * some of them should be moved to other modules eventually

* rename [foo]_contract to just foo
        * contract/dao_contract/ is redundant
        * we can just have contract/dao