Change SBType.GetMemberFunctionAtIndex() to return an object describing the member function in more detail. A type was really quite vague. This now has function name, kind, as well as function type

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@217828 91177308-0d34-0410-b5e6-96231b3b80d8