On the 'move-tracking-2' branch: Implement basic branching operations in the
'svnmover' program.

This program tracks branching and moving info in a rev-prop on revision 0.
It implements operations including 'move', 'branch', 'branchify' and 'list
branches'.

This is a demo, a proof of concept. It is not intended for 'production' use.
It is incomplete and has had very little testing. It would be unwise to use
it on an important repository.

* subversion/svnmover/svnmover.c
  (pathrev): Remove.
  (txn_path_join,
   txn_path_str,
   txn_path_to_relpath,
   txn_path_dirname): New utility functions.
  (SVN_ERR_BRANCHING): New, temporary error code.
  (svn_branch_repos_t,
   svn_branch_family_t,
   svn_branch_definition_t,
   svn_branch_instance_t): New types.
  (svn_branch_repos_create,
   svn_branch_family_create,
   svn_branch_definition_create,
   svn_branch_instance_create,
   branch_set_eid_to_path,
   branch_mapping_remove,
   branch_get_eid_by_path,
   branch_get_path_by_eid,
   branch_get_root_path,
   branch_get_sub_branches,
   family_add_new_subfamily,
   family_add_new_branch,
   family_add_new_element,
   family_get_subfamily_by_id,
   repos_get_family_by_id,
   default_repos_info,
   parse_branch_info,
   parse_family_info,
   parse_repos_info,
   fetch_repos_info,
   write_branch_info,
   write_family_info,
   write_repos_info,
   store_repos_info,
   branch_find_subbranch_element_by_location,
   family_find_element_by_path,
   family_get_branch_by_path,
   repos_get_branch_by_path,
   same_branch,
   verify_source_in_branch,
   verify_target_in_branch,
   svn_branch_walk,
   family_list_branch_instances,
   svn_branch_mkdir,
   svn_branch_mv,
   svn_branch_cp,
   svn_branch_branch,
   svn_branch_branchify,
   svn_branch_rm): New functions.
  (mtcc_commit): Don't destroy the pool here -- that belongs to the caller,
    and the caller needs it for a bit longer.
  (action_code_t,
   execute,
   usage,
   sub_main): Update to include branching operations.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1627475 13f79535-47bb-0310-9956-ffa450edef68