Failing testcase for #988
Another attempt to fix #988
Added Coursera class
Revert "Another attempt to fix #988"

This reverts commit 21a72a8b5fc09bdc2b5c8df5c6387c532dc52dc2.
Cherry-pick -flatten: from 3.0
Use `SEL` variable in RACSwizzleRespondsToSelector
Merge pull request #1006 from ReactiveCocoa/copy-3.0-flatten

Cherry-pick RAC 3.0's -flatten: into master
Replaced interval+take1+subscribeNext with afterDelay
Add -[NSUserDefaults rac_channelTerminalForKey:]
RACSequence addition added to NSIndexSet
Remove unused variable
Don't send signals back when sent from the other side
Reive notes taken into account, small odds fixed
NSIndexSet sequence additions TestSpec fixed according to Notes
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