NeoSync 1.2.1

Fixes the server freeze reported in issue #2.

Fixes

• Syncing from a Sable airship no longer freezes the server. Finding your shell container during a sync could force an unloaded chunk to generate on the spot. On a Sable construction this tripped a broken chunk generator and wedged the server thread — after the 10-second sync timer ran out you'd get your movement back, but blocks stopped responding. Shell-container lookups now skip positions whose chunk isn't already loaded instead of forcing generation, on regular levels and Sable sublevels alike.