refactor podspec
refactor podspec

jkoroniak/JKStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,nickelsberry/AXStretchableHeaderTabViewController,nickelsberry/AXStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController,jkoroniak/JKStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,jkoroniak/JKStretchableHeaderTabViewController,faridh/FMStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController,nickelsberry/AXStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController