Add SaveAs File mask

The NPC File saving now support and useful for real works (but, without
result preview, while NPC dynamic config not made)
Add SaveAs file mask for LVL

Added SaveAs filemask for LVL file
Added empty-file write protection. All "save"/"saveAs" action will
working as dummy, without doings, while function QString
WriteLVLFile(LevelData FileData) not made