Clarify some things in README
Clarify some things in README

androidjhent/naver,androidjhent/naver.v2,LinKingR/android-pull-to-refresh,wskplho/android-pull-to-refresh,toker/android-pull-to-refresh,wskplho/android-pull-to-refresh,Ranjan101/android-pull-to-refresh,naver/android-pull-to-refresh,Ranjan101/android-pull-to-refresh,handstudio/android-pull-to-refresh