Make "New Book Options" dialog transient for its caller where possible

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23618 57a11ea4-9604-0410-9ed3-97b8803252fd
Don't create a second account hierarchy page when cancelling the Hierarchy Assistant

Yet another case this could happen: when using Actions->New Account Hierarchy
on an already open book.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23619 57a11ea4-9604-0410-9ed3-97b8803252fd
Bug 720646 - New Book Tabs on Windows

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23620 57a11ea4-9604-0410-9ed3-97b8803252fd
Fix compile warning introduced in r23602

Quote from gnucash-devel:
"I think this introduced a "might be used uninitialized" warning in
src/gnome/top-level.c with my particular version of gcc.

Initializing *file_guid with NULL in gnc_restore_all_state() fixes
the warning, see below."

Author:    Herbert Thoma <herbert.thoma@iis.fraunhofer.de>

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23621 57a11ea4-9604-0410-9ed3-97b8803252fd