Error when encoding strings which contain control characters

[erkyrath]

>>> toml.dumps({"a": "\x01"})

Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python3.7/site-packages/toml/encoder.py", line 47, in dumps
addtoretval, sections = encoder.dump_sections(o, "")
File "/usr/local/lib/python3.7/site-packages/toml/encoder.py", line 209, in dump_sections
unicode(self.dump_value(o[section])) + '\n')
File "/usr/local/lib/python3.7/site-packages/toml/encoder.py", line 160, in dump_value
return dump_fn(v) if dump_fn is not None else self.dump_funcsstr
File "/usr/local/lib/python3.7/site-packages/toml/encoder.py", line 94, in _dump_str
v = [v[0] + joiner + v[1]] + v[2:]
IndexError: list index out of range

This value can be represented in TOML, and in fact the library is able to decode it correctly:

>>> toml.loads( r'a = "\u0001"' )
{'a': '\x01'}

But this input can't be round-tripped:

>>> toml.dumps(toml.loads( r'a = "\u0001"' ))

(same stack trace)

[erkyrath]

#201 looks related; the pull request on that issue may fix this.