split model classes for different line types
renamed line controller to tab line controller
gave tab line controller a TabLine instead of a Line
removed references to header text in map constructor
fixed doc comment for class
added file for chord line controller
give constructor TabLine instead of Line
added default constructors
moved header text stuff to chord line controller
fixed type of model member of chord view controller
moved lyrics line view contorller stuff to a new class
made superclass for line view controllers
removed editable line view controller class
added default constructor for tab line
use correct type to initialize tab line in constructor
changed types from editable line view controller
add line css class in super class
init tabasci controller with all three types of lines
added pubspec file to declare logging dependencies
added packages dir and lock file to ignore file