## About The Pull Request
This makes `/datum/player_details` properly track BYOND version and
build separately, as opposed to just the full version string.
Whenever a client logs in, and their BYOND version is 516, while their
previous version was 515, or vice versa, it'll set a newly added client
var, `rebuild_plane_masters`, to TRUE.
During the `COMSIG_MOB_LOGIN` signal handler of a mob's HUD
(`/datum/hud/proc/client_refresh`), it will check to see if
`rebuild_plane_masters` is TRUE - if so, it will set the appropriate
`relay_loc` of (based on client BYOND version) of its plane master
groups, and rebuild their plane masters.
## Why It's Good For The Game
Makes testing stuff across 515 and 516 easier, as your screen won't
break when switching between the two.
## Changelog
516 is _still_ in private alpha, so no user-facing changes.
b8013f5e76