[MERGE] Implement PreviewTree.stored_kind, PreviewTree.is_executable

[John Arbash Meinel]

John Arbash Meinel has voted tweak.
Status is now: Conditionally approved
Comment:
Again, it seems like you need to test the case where the file *isn't* 
different from the base. Also, you only test stored_kind() for file 
objects, and is_executable() for when it is True. I would like to see at 
least 2 tests for each function, so the test can't pass by just writing 
"def stored_kind(self): return 'file'"



For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C486B877C.5030108%40aaronbentley.com%3E