Merge pull request #1 from TongG/submodular

Completed the submodular.
ADDED doc.
Routine backup.
Merge pull request #2 from TongG/submodular

Some format & ADDED the documentation
Merge pull request #3 from TongG/submodular

Essentially Completed the Formatting
Merge pull request #4 from TongG/submodular

Let the documentation be more graceful.:smile:
UPDATED the file hierarchy of doc directory.