Add INI_STOP_ON_FIRST_ERROR per Robin Getz (defaults to off).
Add unit test baseline with this option on.
See also https://github.com/analogdevicesinc/iio-oscilloscope/commit/f4b25de0399fc811cc1bae974909ee4dd2cb50fa


git-svn-id: http://inih.googlecode.com/svn/trunk@29 f5d6dc10-6d35-11de-b131-07d8e4d3762e