On the 'move-tracking-2' branch: Hide some data members in the branch txn class.
This continues the refactoring to use branch txn/state objects instead of a single 'editor'.
* subversion/include/private/svn_branch.h (svn_branch_txn_t): Move 'first_eid', 'next_eid' from here. (svn_branch_txn_get_num_new_eids): New.
* subversion/libsvn_delta/branch.c (svn_branch_txn_priv_t): Move 'first_eid', 'next_eid' to here. (branch_txn_get_num_new_eids, svn_branch_txn_get_num_new_eids): New. (branch_txn_create): Add it to the vtable. (EID_IS_ALLOCATED, branch_txn_new_eid, svn_branch_txn_finalize_eids, svn_branch_txn_parse, svn_branch_txn_serialize): Track the move.
* subversion/libsvn_delta/branch_nested.c (nested_branch_txn_get_num_new_eids): New. (svn_nested_branch_txn_create): Add it to the vtable.
* subversion/libsvn_delta/branch_private.h (branch_txn_v_get_num_new_eids_t): New. (svn_branch_txn_vtable_t): Add it to the vtable.
* subversion/libsvn_delta/compat3e.c (editor3_alter): Remove an obsolete usage.
* subversion/svnmover/svnmover.c (subtree_replay): Remove direct access to the 'first_eid' field. (allocate_eids): New. (wc_commit): Allocate here instead, using the new method instead of direct access.