Merge pull request #2 from shellylin/master

Add "tasktracer.sh", and skip for empty string when updating process name.
Major changes:
- Create a base class for Task, Process, and Thread, and define pretty_dict().
- Rename data to tasks.
- Use namedtuple for Label.
Use exception handling for parsing error.
New script to get memory offset for each process and get symbols.
Test data for prepare-data.sh
Retrieve task name and update test data.
Fix bug: avoid task name truncation.
Update test data for new logcat format.
Support new log format for BEGIN and END. Remove class NotFoundError.
Temporary fix in skipping empty string of process names.
Root adb before fetching memory maps.