Add svn_diff_file_output_merge3() with cancel support and update callers.

* subversion/include/svn_diff.h
  (svn_diff_file_output_merge3): New function.
  (svn_diff_file_output_merge2): Deprecate.

* subversion/libsvn_diff/diff_file.c
  (svn_diff_file_output_merge2): Replace with ...
  (svn_diff_file_output_merge3): that adds cancel support.

* subversion/libsvn_diff/deprecated.c
  (svn_diff_file_output_merge2): New implementation that just uses
    svn_diff_file_output_merge3().

* subversion/libsvn_wc/conflicts.h
  (svn_wc__mark_resolved_text_conflict): Add cancel support.

* subversion/libsvn_wc/conflicts.c
  (merge_showing_conflicts, eval_text_conflict_func_result,
   resolve_text_conflict, svn_wc__mark_resolved_text_conflict):
    Add cancel support.
  (svn_wc__conflict_invoke_resolver): Pass cancel arguments to
    resolve_text_conflict() and svn_wc__mark_resolved_text_conflict()
  (resolve_text_conflict_on_node): Pass cancel arguments to
    merge_showing_conflicts.

* subversion/libsvn_wc/merge.c
  (do_text_merge): Add cancel support.
  (merge_text_file): Update caller.

* subversion/libsvn_wc/adm_crawler.c
  (restore_file): Update call to svn_wc__mark_resolved_text_conflict().
    Did not add cancel support here.

* subversion/svn/conflict-callbacks.c
  (show_conflicts, merge_prop_conflict, show_prop_conflict,
   edit_prop_conflict): Add cancel support.
  (handle_text_conflict): Update call to show_conflicts().
  (handle_prop_conflict): Update call to show_prop_conflict().

* subversion/tests/libsvn_diff/diff-diff3-test.c
  (three_way_merge): Switch to svn_diff_file_output_merge3().

* tools/diff/diff3.c
  (do_diff3): Switch to svn_diff_file_output_merge3().

* tools/diff/diff4.c
  (do_diff4): Switch to svn_diff_file_output_merge3().



git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1618857 13f79535-47bb-0310-9956-ffa450edef68
Move svn-bench from ./tools into ./subversion.

* tools/client-side/svn-bench: Move from here to ...
* subversion/svn-bench: ... here.

* build.conf
  (__ALL__): Add svn-bench to this list of default binaries.
  (__ALL_TESTS__): Remove it here.
  (svn-bench): Point to the new source path.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1618860 13f79535-47bb-0310-9956-ffa450edef68