Adds `Equatable` constraint to `rx_value<T>`.
Adds `Equatable` constraint to `rx_value<T>`.

hsoi/RxSwift,tottakai/RxSwift,cfraz89/RxSwift,tottakai/RxSwift,kzaher/RxSwift,kzaher/RxSwift,KyoheiG3/RxSwift,thanegill/RxSwift,thanegill/RxSwift,tottakai/RxSwift,hsoi/RxSwift,hsoi/RxSwift,shiratsu/RxSwift,cfraz89/RxSwift,KyoheiG3/RxSwift,shiratsu/RxSwift,ReactiveX/RxSwift,thanegill/RxSwift,kzaher/RxSwift,hsoi/RxSwift,KyoheiG3/RxSwift,kzaher/RxSwift,cfraz89/RxSwift,ReactiveX/RxSwift,cfraz89/RxSwift,shiratsu/RxSwift,ReactiveX/RxSwift,thanegill/RxSwift