Support pinning Network Devices within the UI (context menu)

Previously only possible by editing XML
Relax the Network Device detection timeouts (again)
Refresh statistics for Network Devices every 15 seconds

Upped from 10 seconds
Relax the Network Device stats timeouts
Sticky / Pin discovered Network Devices by default
Sort Network Devices in the UI by IP address and port
Fix the wrong network difficulty displayed for Bitcoin
Merge branch 'feature/pin-network-devices-ui'
Merge branch 'feature/pin-network-devices-default'
Add support for ASICs returning additional (unexpected) STATS results via API
Merge branch 'feature/modified-stats-support'
Merge branch 'bug/wrong-network-difficulty'
Merge branch 'bug/network-devices-unsorted'
Merge branch 'bug/network-devices-disappear'
Merge branch 'bug/blank-network-device-stats'
Update version info