Added keepalive interface to allow controlling the keepalive for specific number of minutes

Signed-off-by: yael <yael@sentileone.com>

refactored keepalive_var to keepalive_internal
change comments
removed -1

Small change in comment regarding keepalive_internal
Merge pull request #151 from yaelmi3/master

Added keepalive interface to allow controlling the keepalive for specifi...