New string API functions; support \s in INI files

[phmccarty]

Some changes were made to libnica in clearlinux/telemetrics-client, so I'm incorporating those here. Also with tests! :-)

[phmccarty]

wow, clang-format segfault in Travis :-(

[phmccarty]

.. and I broke distcheck.

But adding the INI file to EXTRA_DIST leads to an error from abi.sh, so I'll wait to hear back from you first :-)