Difficult to debug UnicodeDecodeError about chameleon

[malthe]

You will now get an output such as:

'ascii' codec can't decode byte 0xc6 in position 29: ordinal not in range(128)

 - Stream:     the artist formerly known as ƤŗíƞĆě
                                            ^
 - Expression: "name | 'undefined'"
 - Filename:   /home/mborch/co/redux/src/chameleon/tests/inputs/greeting.pt
 - Location:   (1:14)

 - Source:     <div>Hello, ${name | 'undefined'}.</div>
                             ^^^^^^^^^^^^^^^^^^
 - Arguments:  decode: <type unicode at 0x7fcab0c22140>
               convert: <function fast_translate at 0x1fb29b0>
               translate: <function fast_translate at 0x1fb29b0>
               name: <classobj name at 0x2210ef0>
               repeat: {...} (0)