- API/CLI/Tcl/GUI: new output option BARCODE_BIND_TOP/--bindtop/

`-bindtop`/"Bind Top"
- DPD: add top boundary (width 3X) by default, using new
  BARCODE_BIND_TOP; "relabel" option; some compliance checks
- GUI: only skip encoded/errored signal processing if active modal
  ExportDialog (wasn't clearing/setting error text bar correctly
  for DataDialog)
- CODE128: debug print checksum
- CODE49/DATAMATRIX/QR/ULTRA: fix uniqueness of errtxt nos
- manual: fuller DPD doc; some spelling typos, formatting

frontend_qt/frontend_qt.pro

@@ -40,6 +40,7 @@ FORMS += extCLI.ui \
          grpDBExtend.ui \
          grpDM.ui \
          grpDotCode.ui \
+         grpDPD.ui \
          grpGrid.ui \
          grpHX.ui \
          grpITF14.ui \