refactor GerritUtil

- extract notification part to NotificationService
- extract rest request part to GerritRestAccess
Merge remote-tracking branch 'remotes/uwolfer/master'
Merge pull request #41 from forrert/features/refactor-gerrit-util

Features/refactor gerrit util
add troubleshoot hint for case when change-list is empty
do Git operations against Gerrit remote

- it just used to take the "first" remote before which was not always the Gerrit one

Resolves #14
bump version to v0.5.0
Merge remote-tracking branch 'origin/master' into intellij13

Conflicts:
	src/main/java/com/urswolfer/intellij/plugin/gerrit/git/GerritGitUtil.java