KFileWizard: split refreshEntry()
FtpFileEngine: clear _entries and _entriesMap before retrieving a list
FtpFileEngine: insert a invalid entry to avoid cache failure

in beginEntryList().
PathComp: isRemotePath(): check more explicitly
PathComp: introduce isRoot() and isDriveList()
PathComp: introduce isFtpPath() and its static family

And fix scheme error, that is, remove the last colon.
Refactorize with PathComp member functions
DirTreeView: remove redundant check
EntryTreeView: remove redundant check
FileIconProvider: missing #include
FtpFileEngine: support filters
FtpFileEngine: remove _entries member variable

Just _entriesMap is enough.
PathComp: add toNativePath()
KFileWizard: use PathComp::toNativePath()
Support completer on a location line