Hashtag highlighting support. Fixes #12
Implement timed task in task model
Implement timed task in task builder
Reflect the change to UpdateTask
Modify @lowjoel visitor
Add DEFAULT_START_TIME
Fix the regression caused in test
Modify @lowjoel tests
Reflect the change in adding task/subtasks/dependencies
Implement serialization of start time
Lint fix
Use templated getOrDefault
Merge pull request #337 from angathorion/hashtags

Hashtag highlighting support.
Merge pull request #341 from evansb/subtask-api

Implement StartTime for timed tasks
SLAP the GetTask
SLAP the batch add subtasks
Decouple things in AddTask
Merge branch 'master' of https://github.com/cs2103aug2014-w10-1c/main into fix-subtask-display-bug

Conflicts:
	You-QueryEngine/internal/action/batch_add_subtasks.cpp
Fix conflict in add task
SLAP UpdateTask