Wordsmithing.
Simplified input data error handling and reporting.
Wordsmithing.
Removed TODOs: decided to keep the name TeX instead of TikZ.
Rename YSeparator to Separator.
Rename x_item_label_width to x_axis_label_width.
Rename x_item_y_coordinate to x_axis_label_y_coordinate.
Rename y_item_label_width to y_axis_label_width.
Rename YItem#name to YItem#description.
Renamed various attributes in Layout.