Update src/bill.c

Added capturing of return values from write() and system() to quiet warnings.
Update src/diag.c

Changed descriptors in fprintf() to match arg type to quiet warnings.
Update src/display.c

Updated descriptors in fprintf() to match arg types to quiet warnings.
Update src/io.c

Added return value capturing on calls to write() to quiet warnings.
Update src/player.c

Added return value capture on call to fgets() to quiet warnings.
Update src/savelev.c

Added capture of return value from write() to quiet warnings.
Update src/scores.c

Changed descriptors in fprintf() to match arg type to quiet warnings.
Merge pull request #1 from ethandicks/master

Ularn code updated to build quietly on modern Linux