Ajax hoverable css hook

[recurve]

Adding an extra hook for CSS rules to latch onto. It will add the class "showHoverable" to the outermost DIV when the hoverable is active. We used this to add an "info icon" to all our hoverables just via CSS rules.

[recurve]

Example CSS:

/** START - AjaxHoverable custom styling **/

.showHoverable.erxHoverArea {
margin-left: 18px;
}

.hiddenHoverableShield:before {
content: "";
left: -18px;
position: absolute;
display: inline-block;
width: 18px;
height: 16px;
}

.showHoverable.erxHoverArea:before {
content: url(../img/information_symbol_16.png);
left: -18px;
position: absolute;
}

/** END - AjaxHoverable custom styling **/