BLK-41 Adds GroupBy to Debouncer

Signed-off-by: Oren Leiman <oleiman@neutral.io>
Fixes Buffer to emit on a schedule rather than on process_signals

Signed-off-by: Oren Leiman <oleiman@neutral.io>
Merge pull request #2 from nio-blocks/feature/debounce_group

Feature/debounce group