Added 3 libraries

Hi,

I just wanted to let you know that I published 3 libraries on github that may be worth listing on your website. 

- http://marvinlabs.github.io/android-intents/
- http://marvinlabs.github.io/android-constrained-widgets/
- http://marvinlabs.github.io/android-progress-panel/

Each library has a free demo app on Google Play and is gradle-ready (on Maven). 

Regards,

Vincent