player lists can manipulate JSON files

- read and write correctly
- needs-work: the minecraft 1.8 server seems to ignore the new items
because the uuids/extra fields are missing. observed: it then deletes
these lines :(
December testing release

- Can read JSON-format player lists from disk to show in UI.
- Can't write to JSON-format, so the only way to manipulate these files
is thru using server commands
Merge branch 'master' into uuid
Merge branch 'master' into uuid
Merge branch 'master' into uuid
rapid release Dec2014-r2