[fix] Fix TU: add propagation delay after write operations

[es-core] Synchro now listen peers changes, throw WebSocket

- Synchro: generate user event from Synchro***Action

- better log prefix on websocket server

- Synchro: use scroll request
- Make sure maven using version >= 3.1

Upgrade to java 1.8
[core] Add config option to reload as part of the BC
[core] Fix unit test config file
[core] Peer: mark peers as DOWN is not alive since X time

Upgrade to java 1.8
[core] Add config option to reload as part of the BC
[core] Fix unit test config file
[core] Peer: mark peers as DOWN is not alive since X time

 - Add new index /page (renamed for old /registry)

- Fix events sent many times - fix #16