Add generic signal handling API to work with boost::asio

This allows providers or the main application to handle POSIX signals
using a callback chain. Each handler can return continueExecution or
breakExecution to stop the signal handling chain or allow it to
continue. Each handler is registered with a priority and upon reciept of
a signal, each handler is executed in priority order until the end of
the list is reached or one returns with breakExecution.

Change-Id: Idd83625eb1a2d3bdafc92bdd839e0d6386177ff2
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
3 files changed