Renamed IMC.currentPageNumber to IMC.currentImageNumber
Display page number and png number in status bar.

TODO: imagenum/folionum are not set until editor is clicked in
In the Notes tab, ctrl-alt-p now adds the folio number, not the image number.
HTML Language check panel. (Work in progress)

TODO:
  * the column resizing is not working well
  * sorting by columns does not resize the rows height
Set background color of words flagged by the dictionary, instead of underlining them, which is easier to see.
Do not highlight scannos by default.
micro-optimization. It's probably faster to test a couple boolean than compute the length of a string.
Fixed off by one line number when importing from guiguts.