Clamps _maxPossibleContentOffset to 0 if lower.
Merge branch 'master' of https://github.com/DocuSignDev/GMGridView
Revert "Adds an option to disable auto horizontal scroll while dragging because it can perform incorrectly." No longer necessary due to change to clamp
_maxPossibleContentOffset
This reverts commit ad2028e4d0e8bea857d44f3cd464a8f29abaeeff.