Merge branch 'release/2.13.0'

Merge pull request #178 from RxSwiftCommunity/release/2-12-4

fix: reentrancy issue with forwardToCurrentFlow

Merge pull request #177 from RxSwiftCommunity/release/2-12-3

project: release 2.12.3

Merge pull request #174 from RxSwiftCommunity/develop

Develop

Merge pull request #170 from RxSwiftCommunity/release/2-12-1

Release/2 12 1

Merge pull request #166 from RxSwiftCommunity/release/2.12.0

Release/2.12.0

project: revert to ios9.0

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'