new syntax for summary strings:

 - ${*expr} now simply means to dereference expr before actually using it
 - bitfields, array ranges and pointer ranges now work in a (hopefully) more natural and language-compliant way
a new class TypeHierarchyNavigator replicates the behavior of the FormatManager in going through type hierarchies
when one-lining summary strings, children's summaries can be used as well as values

llvm-svn: 134458