add failing test for #71
Fixes #71; store local backup of the @_stack, restore it in the ensure block
remove 1.9.2 from travis-ci
Merge remote-tracking branch 'yaauie/issue-71/travel-vs-blocks'

* yaauie/issue-71/travel-vs-blocks:
  Fixes #71; store local backup of the @_stack, restore it in the ensure block
  add failing test for #71