Use Contract owner for unregistering Token

Create directories only if feature is enabled

* Adds error handler in Importer // Import AddressBook #2885

* More robust import #2885

remove -Zorbit=off
switch to rust 1.13

Scrollable accounts in autocomplete

Bump ws-rs

Swap TokenReg dapp from base to decimals

Change beta builds to stable on Travis

refactor copy to clipboard functionality

Dev chain

* fetch known code from the database during restoration

previously it kept all seen code in memory, leading to
high memory usage by the end of state restoration

* whitespace

[ci:skip]

* test previous code fetch

Add a test.

* abort snapshot restoration faster

* flag-checking tests