Make possible app to control page loading message.

[kovrov]

In certain scenarios "loading" message/spinner have to be shown after page loaded. E.g. when fetching additional data via ajax requests in page init.

This patch prevent unwanted hidePageLoadingMsg when option.showLoadMsg set to false.

[johnbender]

@kovrov

This is a good idea for a feature and something we can easily support. I'm going to defer it in the interest of possibly exposing a method during an upcoming navigation refactor. You can view your feature request here:

https://github.com/jquery/jquery-mobile/wiki/Feature-Requests

[kovrov]

The way I see this, it's not a request for a new feature, but rather fixing existing one. As jQuery Mobile user I expect that if I do $.mobile.changePage(to, {showLoadMsg:false}), framework will not call neither showPageLoadingMsg nor hidePageLoadingMsg. This patch just prevent unnecessary call to hidePageLoadingMsg. This should not affect existing user code.