Fix configuration saving, Add timeout configuration, Update Staus page, Fix description for parameters

1. Fix https://issues.jenkins-ci.org/browse/JENKINS-23348 - selenium configuration under jenkins 'manager jenkins' is not saved.
2. Remove deprecated and unused parameters from Configure System page: -rcDebug, -rcLog
3. Add parameter -browserTimeout
4. Set correct description for parameter -timeout (it was changed since selenium v2.21)
5. Remove code which terminates starting selenium node in #startSeleniumNode() in case getHostName() returns null. Reason: node hostname can be manually configured on node in case it is non-discoverable from master. In such case node will successfully starts.
6. Fix Exception when trying to restart hub while it is not running
7. Make connection status visible in Selenium Hub console (set to INFO level). Add connection parameters to log message.
8. Update Status page of plugin. Now it shows actual state (server, port and status) of the HUB.
9. Add Link to original grid console on Status page
10 Add warning to Status page if current hub settings (host/port) was changed but hub was not restarted.