FileLibrary improvements

[GoogleCodeExporter]

The following features should be supported (Feature/Rational):

F: Arbitrary support for filenames.
R: JQuery-UI theme libraries contain currently unsupported filenames such as 
"e6e6e6_40x100_textures_02_glass_75.png".

F: Arbitrary directories for files.
R: JQuery-UI expects certain JavaScript files in a subdirectory, such as 
"ui/i18n/ui.datepicker-
de.js".

F: Arbitrary mime-types for files.
R: Currently mime-types are determined from the file-extension, sometimes it 
would be good to 
have some more control.

F: All editors should be implemented using WAHandlerEditor.
R: There are some parts remaining that show ugly HTML, such as 
WAFileLibraryEditor.

F: FileLibrary uses an ugly hack patching literal values into the compiled 
method at runtime. 
R: This is inherently ugly and hard to port. Rather a class variable should be 
used for caching.

Original issue reported on code.google.com by renggli on 2 Jan 2009 at 10:56