feat(TaskList): change queries to filter out done tasks

Add queries to query all tasks, done or not.

Example:
tasks = getAllTasks();     // returns all undone tasks
tasks = getAllTasks(false);// same as above
tasks = getAllTasks(true); // returns all tasks

BREAKING CHANGE: Change queries to filter out done tasks. As a result,
getTasksWithWord has to be split back into getTasksWithTag and
getTasksWithWord.

Before:
tasks = getAllTasks();
tasks = getTasksWithWord(word, false);
tasks = getTasksWithWord(word, true);

After:
tasks = getAllTasks(true);
tasks = getTasksWithWord(word, true);
tasks = getAllTasksWithTag(word, true);