Compiler: include in full JavaScript files with no Provides directive

More precisely, any JavaScript code not preceded by a 'Provides'
directive is now unconditionally included. This makes it possible to
unconditionally include some JavaScript code. You can insert 'Requires'
directives in this code; the required code will be included as well.
Note that the previous behavior was to ignore any code not preceded by a
'Provides' directive.
Library: indicate that the classList property is not supported by IE9 and propose a workaround