Allow local symbols to be referenced

Local symbols can now be referenced outside the scope of their parent, by using the syntax “Parent.Chlid”.

- Local symbol names are now stored internally as “Parent.Child”.
- The symbol’s scope field no longer forms a linked list of the prior local symbols; it will now always contain the parent.
- Add the ability use EXPORT and GLOBAL with local symbols.
- Reduce duplication between findsymbol() and findpsymbol(), as well as between sym_AddLocalReloc() and sym_AddReloc().

src/asm/globlex.c

@@ -475,6 +475,7 @@ setuplex(void)
 	lex_FloatAddSecondRange(id, '\\', '\\');
 	lex_FloatAddSecondRange(id, '@', '@');
 	lex_FloatAddSecondRange(id, '#', '#');
+	lex_FloatAddRange(id, '.', '.');
 	lex_FloatAddRange(id, 'a', 'z');
 	lex_FloatAddRange(id, 'A', 'Z');
 	lex_FloatAddRange(id, '0', '9');