[MlMt] FIXMEs in Gmail bindings plist

[Ben Klebe]

The Gmail keybindings plist has the following listed as "FIXME." Does 
this mean fix the plist, or add these methods as valid? These options 
seem much better than "toggleReadState:" but they don't appear to be on 
the official keyword list.

> "I" = "toggleReadState:"; // FIXME: Should be ( "markAsRead:", 
> "nextMessage:");
> "U" = "toggleReadState:"; // FIXME: Should be "markAsUnRead:"

Sincerely,

Ben Klebe