Package: Check for both jqueryUi and jQueryUiVersion for ThemeRoller

When constructing the ThemeRoller in the `jquery-ui.theme.css` generation
from the `lib/package.js` file, there are a number of options:
1. We have the `jQueryUiVersion` property available in `this.runtime`.
2. We have the `jqueryUi` property available in `this.runtime`.

The second happens in the jQuery UI release script. The first had to be
introduced as if one calls the `files` method of `jqueryUi`, an instance
of `JqueryUiFiles` is cached under `jqueryUi._files`, creating a circular
reference, since `JqueryUiFiles` objects keep a reference to the `JqueryUi`
ones that created them. Such a circular reference causes a crash since
`node-packager` tries to stringify `jqueryUi`.

Author: mgol

lib/package.js

@@ -285,10 +285,21 @@ extend( Package.prototype, {
 
 		this.themeCssFileNames.push( "theme.css" );
 
-		this.themeroller = new ThemeRoller( {
-			vars: this.runtime.themeVars,
-			version: this.runtime.jQueryUiVersion
-		} );
+		if ( this.runtime.jqueryUi ) {
+			this.themeroller = new ThemeRoller( {
+				vars: this.runtime.themeVars,
+				jqueryUi: this.runtime.jqueryUi
+			} );
+		} else if ( this.runtime.jQueryUiVersion ) {
+			this.themeroller = new ThemeRoller( {
+				vars: this.runtime.themeVars,
+				version: this.runtime.jQueryUiVersion
+			} );
+		} else {
+			this.themeroller = new ThemeRoller( {
+				vars: this.runtime.themeVars
+			} );
+		}
 		this.customThemeUrl = this.themeroller.url();
 		css = this.themeroller.css();