Code refactoring for Feng's work

[szaghi]

The master and testing branches are very old, many progresses have been done with other libraries. To help @fxie2 to be more comfortable, OFF must be updated/refactored.

• [ ] add PENF as third_party dependency;
• [ ] add WenOOF as third_party dependency;
• [ ] add FOODIE as third_party dependency;
• [ ] add support for Travis CI;
• [ ] made a coverage analysis;