-remove missing values before searching fixations
-cast fixations coordinates to int in draw_heatmap
-screen dtype in draw_display depends on file extension
-fix fixation_detection algorithm (last fixation can be lost in case if last row isn't end of fixation)
-remove missing values before searching fixations -cast fixations coordinates to int in draw_heatmap -screen dtype in draw_display depends on file extension -fix fixation_detection algorithm (last fixation can be lost in case if last row isn't end of fixation)