Check for handshake expiration before attempting connection replace

Blocks propagation

Network params.

Add parity-node-zero to bootnodes.

kcov uses travis_job_id instead of coveralls token

Panic on missing counters; Client cleanup

Update README for new PPAs.

Conflicts:
	util/src/journaldb.rs

block_queue::clear should be more thorough

Fixed an issue with forked counters