Revert "Merge pull request #709 from ReactiveCocoa/add-fishhook"

This reverts commit 5043e26d317f992445446d26c78729f5ea2ad422, reversing
changes made to f548b20f5e3f8c540d303ade7256afb0fd4b8208.

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa.xcodeproj/project.pbxproj
Merge pull request #729 from ReactiveCocoa/remove-fishhook

Remove fishhook, disabling automatic iOS backtraces