version bump in podspec (v4.2.9)

Merge pull request #9 from ChatCamp/bug-fixes

Bug fixes

version bump to 4.2.7

fix user chat back button issue

prepare v4.2.5 release

Merge pull request #6 from ChatCamp/bug-fixes

Bug fixes

update podspec to v4.0.1

limit DKImagePickerController

update stating podspec to v4.2.2

update podspec for version 4.2.1