Add peephole optimizer, --help, examples, README update

- Peephole optimizer: eliminates VOID+POP pairs, JUMP-to-next-instruction.
  Adjusts jump targets after dead code removal.
- --help/-h and --version/-v flags.
- 4 example programs: fibonacci, generator, mergesort, objects.
- README rewritten: documents bytecode compiler, --fast flag, all features.
- 529 tests green.

examples/objects.lsp

@@ -0,0 +1,49 @@
+;;; objects.lsp — record types, closures as objects, hash tables
+;;; Run: python3 uncommonlisp.py examples/objects.lsp
+
+;; Record types with inheritance
+(define-record-type <point>
+  (make-point x y)
+  point?
+  (x point-x)
+  (y point-y))
+
+(define-record-type <point3d>
+  (inherit <point>)
+  (make-point3d x y z)
+  point3d?
+  (x point3d-x)
+  (y point3d-y)
+  (z point3d-z))
+
+(define p (make-point 3 4))
+(define p3 (make-point3d 1 2 3))
+
+(display "point: ") (display (point-x p)) (display ",") (display (point-y p)) (newline)
+(display "point3d: ") (display (point3d-x p3)) (display ",")
+  (display (point3d-y p3)) (display ",") (display (point3d-z p3)) (newline)
+(display "point3d is point? ") (display (point? p3)) (newline)
+
+;; Closure-based counter
+(define (make-counter)
+  (let ((n 0))
+    (lambda (msg . args)
+      (cond ((eq? msg 'inc) (set! n (+ n 1)) n)
+            ((eq? msg 'dec) (set! n (- n 1)) n)
+            ((eq? msg 'get) n)
+            ((eq? msg 'reset) (set! n 0) n)
+            (else (error "unknown message" msg))))))
+
+(define c (make-counter))
+(c 'inc) (c 'inc) (c 'inc)
+(display "Counter after 3 increments: ") (display (c 'get)) (newline)
+(c 'dec)
+(display "Counter after decrement: ") (display (c 'get)) (newline)
+
+;; Hash table
+(define ht (make-hash-table))
+(hash-table-set! ht 'name "uncommonlisp")
+(hash-table-set! ht 'version "1.0.0")
+(hash-table-set! ht 'features '(bytecode continuations macros))
+(display "Name: ") (display (hash-table-ref ht 'name)) (newline)
+(display "Features: ") (display (hash-table-ref ht 'features)) (newline)