- Rewrite NinePatchComponent to handle images with a different size than 48x48 px
- It's now possible to change the border sizes using setCornerSize function
Fixes#352 (duplicate).
Fixes#362 (duplicate).
The destructor for AsyncHandle needs to be virtual as its subclasses are
allocated dynamically. I believe this caused the ImageDownloadHandle and its
related resources (such as the HttpReq and its contents) not to be freed
correctly.