py: Make 'bytes' be a proper type, support standard constructor args.

tests/basics/bytes.py

@@ -4,8 +4,36 @@ print(str(a))
 print(repr(a))
 print(a[0], a[2])
 print(a[-1])
+print(str(a, "utf-8"))
+print(str(a, "utf-8", "ignore"))
+try:
+    str(a, "utf-8", "ignore", "toomuch")
+except TypeError:
+    print("TypeError")
 
 s = 0
 for i in a:
     s += i
 print(s)
+
+
+print(bytes("abc", "utf-8"))
+print(bytes("abc", "utf-8", "replace"))
+try:
+    bytes("abc")
+except TypeError:
+    print("TypeError")
+try:
+    bytes("abc", "utf-8", "replace", "toomuch")
+except TypeError:
+    print("TypeError")
+
+print(bytes(3))
+
+print(bytes([3, 2, 1]))
+print(bytes(range(5)))
+
+def gen():
+    for i in range(4):
+        yield i
+print(bytes(gen()))