Checkin versionable nodes

[Alexander Saar]

Hi all,

while working with Sing I noticed that nodes declaring mixin node type  
mix:versionable are not checked in when the initial content is loaded.

This is somehow unexpected to me and can lead to some trouble if you  
rely on versioning. I propose to change this so that versionable nodes  
will be checked in when initial content is loaded. First I started  
thinking about an additional property in the content definition, but  
this is maybe a bit ugly as it results in content definitions that mix  
real content with information how to handle it.

Thus I changed the Loader implementation. it now checks in all  
versionable nodes at the end of the content loading process. For that  
you need to add mix:versionable explicitly in the content definition  
file. It is not enough to declare a primary node type that defines  
mix:versionable, which in my implementation leads to the same results  
as before.

If the team agrees with the proposed changes, I will add an according  
JIRA issue and patch.

WDYT?

Regards,
Alex