Account names - length and characters

[kroggen]

Proposals

1. Allow account names with less than 12 characters (the engine can pad up to 12 characters when making a lookup, if needed)
2. Allow . or - or _ as word separator
3. Also, if possible, allow names with more chars, like 20 or 30
4. Allow to remove/unset a name. This also allows other user to use the name later
5. Allow to set a name to a smart contract in a single call (second argument to v1createName)

[kroggen]

6. Limit the names to lower case letters, to avoid confusing I and l, O and 0
   In this case it should throw an error if upper case letters are used
   Problem: what if used to map token symbol to address? like USDT
7. Allow unicode characters (UTF-8) (may affect the above)

[kroggen]

8. Allow smart contracts to transfer names
9. Approvals: approve another account as an operator, to transfer the name
10. Add method to check the ownership of a name (at least to smart contracts, like name_service.owner() or alike

[kroggen]

11. Remove charging for transferring a name (v1updateName). Currently it is charging twice when setting a name to a smart contract
12. Expiration and Renewals? What if the owner dies? Or the access to the private key is lost?