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.

tests/programs/common_test.bas

@@ -0,0 +1,6 @@
+10 REM COMMON test - verify variables preserved across CHAIN
+20 COMMON X, N$
+30 X = 42
+40 N$ = "hello"
+50 Y = 99
+60 CHAIN "tests/programs/common_target.bas"