Started refactoring IDocumentContentOperations out of SwDoc.

The work all done except for moving all calls to the interface's functions
from SwDoc::.. to SwDoc::getIDocumentContentOperations::..
I didnt do that yet in case we make some design change.

Things I had to change that are not simply refactoring:

Made SwNodes in sw/inc/ndarr.hxx friend class to
DocumentContentOperationsManager so it can call DelNodes at end of
DocumentContentOperationsManager::DeleteSection .

Added DeleteAutoCorrExceptWord to SwDoc, its needed in the Manager.

Added a non const version of SwDoc::GetDfltGrfFmtColl() to SwDoc
because its needed in the Manager.

Made SwDoc a friend class to DocumentContentOperationsManager so it
can call SwDoc::checkRedlining and SwDocL::_MakeFlySection.

Moved SwDoc::CopyImpl_ , SwDoc::CopyWithFlyInFly and
SwDoc::CopyFlyInFlyImpl into the Manager.

Moved "struct ParaRstFmt" and "lcl_RstTxtAttr" from docfmt.cxx
in DocumentContentOperationsManager.hxx .

Other things I noticed:

Why are sw_GetJoinFlags and sw_JoinText apparently global functions
defined in docedt.cxx . It looks like they should be moved somewhere.
They are only used in this Manager and one other place.

UpdateParRsid and UpdateRsid where grouped under
IDocumentContentOperations in SwDoc but  are not part of the interface.

Change-Id: Icaab57f4a8c158a85e549ecb4aacc752bc95bbc9