Null pointer check

Players who haven't joined your server since the UUID conversion will have a null name. As a result, if you try to /openinv a player who *has* joined your server since then, the loop can break due to a NPE while checking other players. This null check should fix that problem.
Add brackets to avoid ambiguity

Java ignores indentation, which might cause headaches in the future.
Merge pull request #10 from Fysac/master

Null pointer check