Re-enabling warn as error and cleaning out dead file.

Author: sean-parent

documentation/asl/version_0.dox

@@ -978,7 +978,7 @@ WARN_LAYOUT_FILE       = YES
 # Possible values are: NO, YES, FAIL_ON_WARNINGS and FAIL_ON_WARNINGS_PRINT.
 # The default value is: NO.
 
-WARN_AS_ERROR          = NO
+WARN_AS_ERROR          = FAIL_ON_WARNINGS_PRINT
 
 # The WARN_FORMAT tag determines the format of the warning messages that Doxygen
 # can produce. The string should contain the $file, $line, and $text tags, which