Added -reduceAll and -reduceAny in #660

Only accepts a RACTuple of NSNumbers
Gone for @kastiglione's naming
Managed to invert the operators with a find & replace
Fixed some style issues for reduceByAnd/Or
Fixed indentation in reduceByAnd
Change reduceByAnd/Or to just and/or
Add -[RACSignal initially:]
Merge branch '2.0-development' into racsignal-initially
Add -intially: to the CHANGELOG
Remove +switch:cases:, change missing default behavior

A missing default now sends an error instead of throwing an assertion
failure.
Inline RACSwitchSignalExamples back into RACSignalSpec
Test that a missing case and default causes a signal error
Match nil values as RACTupleNil
Fix duplicate subscriptions in tests
Update README for 2.0 deprecations
Update MemoryManagement.md
Update BasicOperators.md
Update DesignGuidelines.md
Shout out to RACBacktrace in the Framework Overview
Refactor -initially: to use +defer: internally