Lift in-memory delta tree construction code from svnmucc and drop it into the  Delta Editor -> Ev2 compat shim.
Lift in-memory delta tree construction code from svnmucc and drop it into the 
Delta Editor -> Ev2 compat shim.

This is something of a checkpoint commit.  The code compiles, but doesn't do
much more than that (it isin't even invoked).  This code is still very 
ra session-centric, but will be generalized in a subsequent commit.

* subversion/libsvn_delta/compat.c
  (action_code_t, operation): New types.
  (get_operation, subtract_anchor, build): New.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion