add some troubleshooting hints for common problems
add some troubleshooting hints for common problems

Related to #29
Related to #39

uwolfer/gerrit-rest-java-client,sstafford/gerrit-rest-java-client,eekboom/gerrit-intellij-plugin,vogellacompany/gerrit-rest-java-client,vogellacompany/gerrit-rest-java-client,uwolfer/gerrit-rest-java-client,sstafford/gerrit-rest-java-client,uwolfer/gerrit-intellij-plugin