Make PCAP handlers deregister from this list when they are destructed. This avoid the signal handler calling destructed objects under very rare circumstances.
Move emergency handlers header file into the support folder.
Refactored signal handling:
- Remove the dependency with the running static variable in the header file.
- Move implementations down to cc files.
- Allow specifying a new signal handler that will be used to stop the applications.
- Move signal handling files to support.