I've entered a bug and attached a patch to both fix a minor build issue (typo in makefile) and to update the Developer Guide to show the correct use of ENC_BIG_ENDIAN rather than FALSE in the final argument of proto_tree_add_item() calls. It might be worth reviewing further to see if some of those calls in the documentation might be changed to proto_tree_add_uint() or similar. It would be a shame if outdated documentation caused new dissector writers to undo some of the work that has been accomplished lately.
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6482
Ed