additional default wget command-line option: "--progress=dot:binary"

notes regarding my own testing of wget.exe binaries under Windows:

* the binaries that I use come from:
    http://opensourcepack.blogspot.com/2010/05/wget-112-for-windows.html

* my initial tests were using wget-1.14:
    http://osspack32.googlecode.com/files/wget-1.14.exe
  observations:
    - the continue "-c" switch to resume broken downloads doesn't work properly

* subsequent tests were using wget-1.16:
    http://sourceforge.net/projects/tumagcc/files/wget-1.16.7z/download
  observations:
    - download continuation "-c" works perfectly
    - the default progress indicator is fairly horrible.
      _this_ commit adds another switch to configure the display of this indicator.