Grove Button Example Application with GPIO interrupts.

[vintummala]

Signed-off-by: Vineela Tummalapalli vineela.tummalapalli@intel.com

[vintummala]

Do Not Merge.
This application is tested only with locally generate UPM/MRAA AAR files. It works fine.

Note: On Joule, not all GPIO pins are currently enabled for input interrupts. To see the GPIO pins with input interrupts enabled, see the below documentation
https://software.intel.com/en-us/articles/installing-android-things-on-intel-joule-module

@bjbeare , please let me know if this has to be mentioned in README or not.

[bjbeare]

I don't think that we need to indicate the interrupt status of pins on Joule.
Did the interrupt code get pushed to the public upm/mraa repository yet?
If so... should we merge this?

[vintummala]

This could be part of http://iotdk-ninja.amr.corp.intel.com/repositories/io/mraa/at/.
I do not see any new version in Jcenter but i can re-check.