Fix richToolTip so that it can be used from a modal dialog

Moved the code which appends the tooltip content to body to the 'show' function, so that this occurs only if the user clicks on the tooltip.
If the tooltip element has an explicit z-index it inherits from a parent, bump it up by 1. In case the tooltip is used in controls like modal dialogs, this will show the tooltip.
For all other cases, the behavior remains as before.