Add failing test for -respondsToSelector: with -rac_signalForSelector:
Replacing implementation of -respondsToSelector: should validate if the instance has a signal for the selector
Fix typo
Remove exception test
Improve evaluation order

Save accessing a associated object until we've verified that the method exists.
Revert "Improve evaluation order"

This reverts commit dcc51078a06c504dc0c3a5cc4754e8d45eb76b83.
Improve evaluation order

Save accessing a associated object until we've verified that the method exists.
Remove indent at blank lines
Merge pull request #926 from ikesyo/fix-respondstoselector-replacement

Fix to -rac_signalForSelector: properly implement -respondsToSelector: for optional method from a protocol