fix Issue #7 - $.browser is deprecated

- Refix Issue #6 properly.

- Always set `overflow-y: hidden;`, it avoids the flickering
  scrollbar on IE and is correct for other browsers as well.

- Don't set the target to minHeight before measuring,
  this causes heavy jumping for IE8, but seems to
  be totally unecessary.

- Also remove scroll(scrollTop = 0), testing didn't
  reveal any usefulness of this.

Tested with IE8, IE10, Chrome 31 and FF 26.0.