Autodetect when it is necessary to use careful parsing.

[Aluriak]

Careful parsing should be the default choice in 0.4.0 In 0.3.x though, it could be activated if:

• there is nested parenthesis (i.e. ( is followed by a (, not a ))
• there is a paren between two double-quotes

The former is easy to test. The latter is harder, but together will match most cases where the naive parsing is not enough.