(PSDRV_AFMGetCharMetrics): Use unsigned chars (since isspace is used).

(PSDRV_AFMGetCharMetrics): Use unsigned chars (since isspace is used).
(PSDRV_AFMParse): Don't crash on missing font name.  Use unsigned
chars.  Fix peculiar inconsistent indentation.  Don't leak a FILE.
Catch problematic files with no line feed in them.  Don't mix
characters and integers.  Don't overrun the buffer.