HTML Language check panel. (Work in progress)

TODO:
  * the column resizing is not working well
  * sorting by columns does not resize the rows height
Added command line options: version and filename.
Do not crash when the dict/ directory is not found.
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.