terminal code eaters: implement OSC

This is a useful piece of functionality to being able to eat URL
hyperlinks, for instance, which is a bug that Lix has while dealing with
terminal output today.

Change-Id: I77b2de107b2525cad7ea5dea28bfba2cc78b9e6d

tests/functional2/testlib/test_terminal_code_eater.py

@@ -0,0 +1,8 @@
+from functional2.testlib.terminal_code_eater import eat_terminal_codes
+
+
+def test_eats_color():
+    assert eat_terminal_codes(b'\x1b[7mfoo blah bar\x1b[0m') == b'foo blah bar'
+
+def test_eats_osc():
+    assert eat_terminal_codes(b'\x1b]8;;http://example.com\x1b\\This is a link\x1b]8;;\x1b\\') == b'This is a link'