Added ex mode to line editor, a 'keymap' builtin, and a zsh-like widget system using ':!<shellcmd>' ex mode commands

src/builtin/mod.rs

@@ -25,13 +25,14 @@ pub mod map;
 pub mod arrops;
 pub mod intro;
 pub mod getopts;
+pub mod keymap;
 
-pub const BUILTINS: [&str; 44] = [
+pub const BUILTINS: [&str; 45] = [
   "echo", "cd", "read", "export", "local", "pwd", "source", "shift", "jobs", "fg", "bg", "disown",
   "alias", "unalias", "return", "break", "continue", "exit", "zoltraak", "shopt", "builtin",
   "command", "trap", "pushd", "popd", "dirs", "exec", "eval", "true", "false", ":", "readonly",
   "unset", "complete", "compgen", "map", "pop", "fpop", "push", "fpush", "rotate", "wait", "type",
-	"getopts"
+	"getopts", "keymap"
 ];
 
 pub fn true_builtin() -> ShResult<()> {