Update DefaultResourceLoader to always attempt FileResource resolution before URLResource, allowing casting of the result to WritableResource.

Also update ResourceEditorRegistrar to register a property editor for WritableResources.

Issue:

Comment From: cbeams

Hey @philwebb, I don't know the larger context here, but thought I'd check: are you aware that FilesystemResourceLoader already attempts FileResources by default?

Comment From: philwebb

I see that is the case for paths starting with '/'. The context here is supporting:

@Value("file:/some/file") WritableResource resource. 

Currently the above will only work with Resource

Comment From: snicoll

Sorry this was overlooked for so long @philwebb. This got superseded in the meantime as of 5.0.2.