Fix go vet nitpicks.

Fixes #130:
* pass by reference into AllowAnonymous
* check return value of From() rather than value of From function

auth.go

@@ -54,7 +54,7 @@ func NewAuth() *Auth {
 }
 
 // AllowAnonymous determines if anonymous users are permitted.
-func (a Auth) AllowAnonymous() bool {
+func (a *Auth) AllowAnonymous() bool {
 	return a.whitelist.Len() == 0
 }
 

chat/command.go

@@ -62,7 +62,7 @@ func (c Commands) Alias(command string, alias string) error {
 
 // Run executes a command message.
 func (c Commands) Run(room *Room, msg message.CommandMsg) error {
-	if msg.From == nil {
+	if msg.From() == nil {
 		return ErrNoOwner
 	}