Fixes warning: multiple methods named 'postNotificationName:object:' found [-Wstrict-selector-match]
Fixes warning: multiple methods named 'objectForKey:' found [-Wstrict-selector-match]
Fixes warning: weak receiver may be unpredictably set to nil [-Wreceiver-is-weak]

Signed-off-by: Mattt Thompson <m@mattt.me>