add dao which takes care about all CRUD operations on storage
remove blockchain state since everything is stored on change
remove storage operations from structs(entities)
move structs to entities package
Fixes things like:
* exported type/method/function X should have comment or be unexported
* comment on exported type/method/function X should be of the form "X ..."
(with optional leading article)
Refs. #213.
* func to get private key from raw bytes
* added function to create raw transfer tx
* fixes
* more fixes
* prettify code and comments; neoscan interaction put in dedicated files
