<rdar://problem/12523238> Commit 3 of 3

Changed all relevant test cases to verify that MightHaveChildren() works correctly for objects of interest
Added a bunch of convenience methods for test cases to use: target(), process(), thread() and frame() which mimic the lldb.X convenience variables
As a bonus, edited the documentation on the website to describe the new method available for synthetic children providers writers to implement!

That's all folks!

llvm-svn: 166535