Fixed a problem and made some improvements

[zhcnxf]

Changes:

• Fix a problem, see issue#92
• Add an option to generate sources for library.
• Introduce gradle

[13rac1]

IDK exactly how @BoD wants to run this project, but normally this should be three separate PRs especially with how many lines are changed.

[zhcnxf]

@eosrei Thanks, I'll see to it. I really like this project and hope it goes well.