Correct quote parsing and allow for 'escaping' quotes

[RobSanders]

Currently cli_parse_line() is not correctly several types of lines with quotes. For example (ignore quotes for the 'parsed' output):

• mixed double and single quotes show 'alpha"bravo" charlie' parsed as 3 words (1)"show" (2)"bravo" (3)\<emptystring>
• lines with non-whitespace immediately before or after the quoted string show alpha,"bravo",charlie parsed as 3 words (1)"show" (2)"bravo" (3)",charlie"
• no way to 'escape' a quote within a quoted string show "alpha,"bravo",charlie" parsed as 3 words (1)"show" (2)"alpha," (3)",charlie"

Note that in all 3 cases text is lost. Ideally libcli should support:

• balanced quotes (accept all characters until next matching quote found)
• escaping a quote using the '\' character so it is treated as a literal (deal with escaping the escape as well)

Open question on how two properly quoted strings without whitespace separating them should be handled. Combined into a single string, or converted into two separate tokens?

[RobSanders]

Currently when libcli detects a 'new' quote it starts a new word(possibly discarding anything before the new quote). So parsing the fragment \<"alpha"beta> you would get words \<alpha> and \<beta>. Suggest with the patch that libcli should treat any (unless escaped) quote as an implicit 'word' separator.

[RobSanders]

Fixed in 1.10.3