Revert to switching to the APP flags when making a copy of the key/value.  This is required to support the following sequence:

 - set_key
  - KEY_APP flag set
 - search
  - success, RET flags set
 - remove
  - key copied, RET flag stays set
  - deadlock, RET flags cleared
 - retry remove
  - fails: neither KEY_APP or KEY_RET is set

refs #607
Don't clear the key after a cursor remove.
refs #607
Make a copy of the key after a successful remove.
refs #607
Rename cursor flags KEY/VALUE_INT/EXT to clarify that they track whether the key/value points into the tree or out of the tree.
whitespace
Merge pull request #612 from wiredtiger/cursor-flags

More refinement to cursor key/value handling on error and after remove.