Eval a command in CL-USER package.

This commit fixes a "command not found" error when loads a shlyfile which is compiled by "shly compile-file".
Because "shly compile-file" binded the current package to SHELLY.CORE by default.
Prevent loading an init file when (dump-core :quit-lisp nil).
Prevent invoking a debugger when a requested system (-L something) is not found.
Updated bin/shly.