add setPid() method
set pid during node creation
add pid's to links
handled by ioHandler tests
use pid, have node walking work with both pids and node ids
start using ioid
make output work with pids
actually make use of one IOHandler
initialize iip within empty nodeId and port, revert ioHandler being singleton
Merge branch 'feature/implement_pids' into develop
Merge pull request #29 from psichi/develop

Implement pids