Merge pull request #218 from github/backtrace-fixes

Fix backtrace logging with RACSchedulers, add unit tests
Merge pull request #230 from github/fix-flatten-documentation

Fix documentation for -[RACStream flatten]
Implemented RACLazyProperty.
Fixed RACLazyProperty not handling synchronous start signals correctly.
Added test for -nonLazyValues to check for sending default value.
Implemented -nonLazyValues.
Added RACLazyProperty.h to umbrella header.
Merge branch 'master' into two-way-binding

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa.xcodeproj/project.pbxproj
Merge branch 'master' into demo-infinite-spinner

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa.xcodeproj/project.pbxproj
	ReactiveCocoaFramework/ReactiveCocoa/RACAsyncCommand.m
Merge branch 'master' into subscriber-multiple-subscriptions
Handle nil disposables
Fix indentation in RACSubscriberExamples.h
Merge branch 'master' into signal-name-debugging

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/RACSignal+Operations.m
Merge pull request #229 from github/subscriber-multiple-subscriptions

Support multiple signals per subscriber, fix -concat
Merge pull request #223 from github/demo-infinite-spinner

Remove RACAsyncCommand, fix infinite spinner in GHAPIDemo
Merge branch 'master' into signal-name-debugging

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/RACSignal+Operations.m
Add a name for +if:then:else:
Merge branch 'master' into two-way-binding
Merge pull request #225 from github/signal-name-debugging

Automatically set stream, signal, and sequence names
Refactor +interval: tests to handle delayed intervals

Since a delay will make the next value appear to send too soon, we need
to calculate our expected results from the base time, and not save a
delta at each step.