Add length check to IsValidPlayerName.

Also check for the maximum allowed length in IsValidPlayerName, and
rework the code internally a biAdd length check to IsValidPlayerName.

Also check for the maximum allowed length in IsValidPlayerName, and
rework the code internally a bit.
Check for valid names in name_new.
Merge pull request #47 from domob1812/name-new-checks

Add checks for valid player name in name_new.