Package fragment classes now are named "*Package-<filename>-<hash>" instead of
"*Package$src$<filename>$<hash>". This will help to avoid erroneous code in
intellij FileManager, which assumes that classes with dollars are always inner
classes of some other class (see AnnotationDescriptorDeserializer)
JetPositionManager now finds a PsiFile to create a SourcePosition correctly.
This fixes problems with breakpoints and navigation between frames when there's
more than one file with the given name (not necessarily in the same package)