Polishing Actually enable fat db pr (#1974) (#2048)

* Actually enable fat db, and do RPCs for it.

* Implement HashDB traits for AccountDB.

* user defaults

* finished user defaults

* user defaults are network-dependent

* added tests for newly added functions, logger is initialized first

* dir cleanup in progress

* user_file is placed next to snapshots

* fixing requested change

evmbin/src/main.rs

@@ -123,7 +123,6 @@ impl Args {
 	}
 }
 
-
 fn die(msg: &'static str) -> ! {
 	println!("{}", msg);
 	::std::process::exit(-1)