Fix cli that would play all scripts

tests/test_output.py

@@ -0,0 +1,24 @@
+import pytest
+from shlax import Output
+
+
+class Write:
+    def __init__(self):
+        self.output = ''
+    def __call__(self, out):
+        self.output += out.decode('utf8')
+
+
+@pytest.fixture
+def write():
+    return Write()
+
+
+def test_output_regexps(write):
+    output = Output(
+        regexps={'.*': {0: 0}},
+        write=write,
+        flush=lambda: None,
+    )
+    output('foo')
+    assert write.output == output.colorize(0, 'foo')