Add AUTO, RENUM, DELETE, COMMON; fix LIST range parsing

AUTO generates line numbers during interactive editing, RENUM
renumbers program lines and patches all GOTO/GOSUB/ON references,
DELETE removes line ranges. COMMON declares variables preserved
across CHAIN. Also fixed LIST/DELETE range parsing (was broken by
expression evaluator consuming the dash as subtraction).

Bump to v0.7.0, 53 tests.

include/gwbasic.h

@@ -10,7 +10,7 @@
 #include "gw_math.h"
 #include "strings.h"
 
-#define GW_VERSION "0.6.0"
+#define GW_VERSION "0.7.0"
 #define GW_BANNER "GW-BASIC " GW_VERSION
 
 /* Tokenizer */

include/interp.h

@@ -64,6 +64,15 @@ typedef struct {
     uint8_t *err_resume_text;
     program_line_t *err_resume_line;
     uint16_t err_line_num;
+
+    /* AUTO mode */
+    bool auto_mode;
+    uint16_t auto_line;
+    uint16_t auto_inc;
+
+    /* COMMON variable list for CHAIN */
+    int common_count;
+    struct { char name[2]; gw_valtype_t type; } common_vars[64];
 } interp_state_t;
 
 extern interp_state_t gw;