version 0.1.6, 2016-08-07 -- fix error in some calculations involving total internal reflection, add an example (sample6, a surface plasmon resonance calculation) that now works but previously did not.
version 0.1.7, 2017-02-15 -- add E-field calculation to position_resolved(), edit find_in_structure() to make it easier to use position_resolved() for the 0'th layer, and minor formatting and documentation cleanup.