EntryTreeView: ignore drag and drop on a drive list
EntryListModel: override rootPath()

to apply fixUrl().
KFileWizard: disconnect directoryLoaded() properly

This fixes the problem that a dir tree scrolls to the current entry when
expanding other entry.
KFileWizard:: Refactorize by introducing copyUrlsTo() and removeUrls()
EntryTreeView: use event->keyboardModifiers()

QApplication::queryKeyboardModifers() was APIs introduced since 4.8. For
the compatibility, do not use it.
EntryTreeView: use event->dropAction()
PathComp: use _path not path
FtpFileInfoCache: a new path can have a different dir from a old path
Add support of drag and drop to dir view
EntryTreeView: support to drag and drop to a directory entry
EntryTreeView: simplify and more strict check
PathComp: prevent out-of-bounds of QString::at()