1.0.3: Advanced tasks_info & Improve Developer Experience

Feature: advanced tasks_info

• Refactored make_tree_info #234 by @mski-iksm
• Add dump_task_info_table #235 by @mski-iksm
• Dump task info tree object to a pickle file #241 by @mski-iksm

Improvement: Developer Experience

• Fix conf file for local test #239 by @mski-iksm
• Added example notebook #236 by @mski-iksm
• add __init__.py to run all test at unittest #240 by @mski-iksm
• raise GokartbuildError on gokart.build failed #237 by @snowhork