Use `SEL` variable in RACSwizzleRespondsToSelector
Add -[NSUserDefaults rac_channelTerminalForKey:]
Remove unused variable
Don't send signals back when sent from the other side
Style: spaces around BOOL
Merge pull request #1010 from ikesyo/swizzling-use-selector-var

Use `SEL` variable in RACSwizzleRespondsToSelector
Expect BOOLs, not NSNumbers
Add NSUserDefaults+RACSupport.h to ReactiveCocoa.h
Merge pull request #1018 from ReactiveCocoa/user-defaults

Add an extension to `NSUserDefaults` to create a channel for a key
Make NSUserDefaults+RACSupport.h public
Merge pull request #1021 from ReactiveCocoa/fix-user-defaults-header

Make NSUserDefaults+RACSupport.h public
Make NSUserDefaults+RACSupport.h more public
Merge pull request #1022 from ReactiveCocoa/fix-user-defaults-header-more

Make NSUserDefaults+RACSupport.h more public