<rdar://problem/12042982>

This radar extends the notion of one-liner summaries to automagically apply in a few interesting cases

More specifically, this checkin changes the printout of ValueObjects to print on one-line (as if type summary add -c had been applied) iff:
this ValueObject does not have a summary
its children have no synthetic children
its children are not a non-empty base class without a summary
its children do not have a summary that asks for children to show up
the aggregate length of all the names of all the children is <= 50 characters
you did not ask to see the types during a printout
your pointer depth is 0

This is meant to simplify the way LLDB shows data on screen for small structs and similarly compact data types (e.g. std::pair<int,int> anyone?)

Feedback is especially welcome on how the feature feels and corner cases where we should apply this printout and don't (or viceversa, we are applying it when we shouldn't be)