cameo: split numbers into dimensions and "bare" numbers

- lang.l, lang.y (MIL2MM): moved unit conversion from lang.l to lang.y
- lang.l, lang.y: instead of returning dimensions and numbers as NUMBER,
  return as NUM_EXP_<unit> for numbers with an explicit unit, and as
  NUM_IMP_<unit> if the unit is implied
- lang.y (dimen): perform unit conversion as needed
- lang.y (number): never convert and only accept implicit dimensions
- lang.y: change all uses of NUMBER to "dimen", except for the
  multipliers in "array", where we can now use "number"
- lang.y: removed comment about "array" only working in metric mode

cameo/lang.l

@@ -24,9 +24,6 @@ static int lineno = 1;
 static int metric = 1;
 static int file_name_follows = 0;
 
-
-#define	MIL2MM(mil)	((mil)/1000*25.4)
-
 %}
 
 /* file name can contain any characters */
@@ -69,17 +66,15 @@ NUM	-?[0-9]+\.?[0-9]*
 {NUM}mm				{ yylval.num = strtod(yytext, NULL);
 				  if (file_name_follows)
 					BEGIN(FILENAME);
-				  return NUMBER; }
-{NUM}mil			{ yylval.num = MIL2MM(strtod(yytext, NULL));
+				  return NUM_EXP_MM; }
+{NUM}mil			{ yylval.num = strtod(yytext, NULL);
 				  if (file_name_follows)
 					BEGIN(FILENAME);
-				  return NUMBER; }
+				  return NUM_EXP_MIL; }
 {NUM}				{ yylval.num = strtod(yytext, NULL);
-				  if (!metric)
-					yylval.num = MIL2MM(yylval.num);
 				  if (file_name_follows)
 					BEGIN(FILENAME);
-				  return NUMBER; }
+				  return metric ? NUM_IMP_MM : NUM_IMP_MIL; }
 
 <FILENAME>[^ \t\n]+([^\t\n]*[^ \t\n]+)? {
 				  BEGIN(INITIAL);