symset properties (trunk only)

Pat Rankin wrote:
> Symbol set definitions need a description attribute, above and
> beyond allowing comments in the file, for inclusion in the 'O'
> command's menu entries for selecting them.
[...]
> mapglyph.c isn't the proper place to decide whether to define
> ROGUE_COLOR.  That may need to become a symbol attribute,
> which we'd then specify on the Epyx rogue set(s).

Implement both of the suggestions above.

sys/share/pcmain.c

@@ -307,11 +307,11 @@ char *argv[];
 
 #if defined(MSDOS) || defined(WIN32)
 	/* Player didn't specify any symbol set so use IBM defaults */
-	if (!symset[PRIMARY]) {
+	if (!symset[PRIMARY].name) {
 		load_symset("IBMGraphics_2", PRIMARY);
 	}
 # ifdef REINCARNATION
-	if (!symset[ROGUESET]) {
+	if (!symset[ROGUESET].name) {
 		load_symset("RogueEpyx", ROGUESET);
 	}
 # endif