Begin to refactor WebFoundation in preparation for some planned API changes.
	This change removes all WebResourceHandle subclasses, pushing the functionality
	that was contained in those classes to the corresponding WebProtocolHandler
	subclasses. To make this work, I also did a small amount of mime type cleanup, and
	as a bonus, I (unintentionally) managed to fix these two bugs:

	Radar 3034795 (README fiel displays as HTML even though it's plain text)
	Radar 3035320 (iana.org character sets page displays as HTML even though it's MIME type text/plain)

	Bonus! :-)

	Removed:

	* CacheLoader.subproj/WebAboutResource.h
	* CacheLoader.subproj/WebAboutResource.m
	* CacheLoader.subproj/WebFileResourceHandle.h
	* CacheLoader.subproj/WebFileResourceHandle.m
	* CacheLoader.subproj/WebHTTPResourceHandle.h
	* CacheLoader.subproj/WebHTTPResourceHandle.m

WebKit:

        * WebView.subproj/WebControllerPrivate.m:
        (+[WebController _MIMETypeForFile:]): Small tweak to account for change
	in behavior of a WebFoundation method upon which this method depends.
	The WebFoundation now returns nil when it cannot find a suitable mime
	type rather than returning a default. This function now checks for a nil
	return value and sets @"application/octet-stream" in that case.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@1944 268f45cc-cd09-0410-ab3c-d52691b4dbfc