FACES-1898 Develop alloy:dialog, alloy:outputTooltip, and alloy:popover components (Added abstract tags in the components-ext.xml to avoid unnecessary copy/paste. Moved headerText and autoHide from hidden attributes to generated code by specifying <yui>true</yui> and a <yuiName> for both of them. In OutputTooltip changed the cssClass attribute to be the yuiName of the styleClass attribute. Overrode encodeCssClass() to utilize encodeNonEscapedString().)