save draft comments in Gerrit

- get rid of ReviewCommentSink

Resolves #98
set correct line, range and side in reply-to-comments

Resolves #99
prevent possible NPE
bump version to v0.9.0
Merge remote-tracking branch 'origin/master' into intellij13

Conflicts:
	src/main/java/com/urswolfer/intellij/plugin/gerrit/ui/diff/AddCommentAction.java
	src/main/java/com/urswolfer/intellij/plugin/gerrit/ui/diff/CommentsDiffTool.java
	src/main/java/com/urswolfer/intellij/plugin/gerrit/ui/diff/RemoveCommentAction.java