EditorManager: Add NoNewSplits to OpenEditorFlags

This is used together with OpenInOtherSplit to suppress creation
of a new split if none are currently in use.

Change-Id: Ied97dcd6a756518bcf8bbe1d815cb2df9b872bfc
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
VCS: Open diff/blame editors in other split

... if there are other splits that is.

Task-number: QTCREATORBUG-11623
Change-Id: Icb3b1c86c39d88e90916079e8ab347574ae9a361
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Beautifier: add punctuation to messages

Change-Id: I7cba7d2d88459c26af31d89a2fd3cd31b6fbe62d
Reviewed-by: Lorenz Haas <lykurg@gmail.com>
Reviewed-by: hjk <hjk121@nokiamail.com>