Functions to prepare and analyse eye tracking data of reading
exercises. The functions allow some basic data preparations and code fixations
as first and second pass. First passes can be further devided into forward and
reading. The package further allows for aggregating fixation times per AOI or
per AOI and per type of pass (first forward, first rereading, second). These
methods are based on Hyönä, Lorch, and Rinck (2003)