Add tooltip when hovering over user variables

[nevadascout]

Wire up ToolTipNeeded event handler on FCTB.

Example usage:

if (!string.IsNullOrEmpty(e.HoveredWord))
{
    e.ToolTipTitle = e.HoveredWord;
    e.ToolTipText = "This is tooltip for '" + e.HoveredWord + "'";
}

[nevadascout]

Can use the lexer in 2.0 to add contextual detail to the tooltip