Add editing conditional to view

Check the boolean'isEditing' inside each todo. If true, then replace the
contents of the the todo with a text input, if false display the label
with the current task.

Also adds a double click action binding to the label, this will execute
the 'editTodo' method on 'TodoController' upon being well, double clicked.
Add 'edit' methods and properties to TodoController

This adds an action method called 'editTodo' to the TodoController, which
corresponds with the action set in the template upon double clicking. It
sets the 'isEditing' boolean to true, thus showing the edit view.

This also adds the isEditing property with an initial value of false.
Add git logging script