* Some changes for the Windows build to the project file (preliminary), including
  replacing calls to sqrt() with qSqrt(). The Windows compiler was confused, and
  I should have been using qSqrt() anyways. Added .ico and .rc files to give it
  an icon in Windows.
* Fixed a nasty bug where I wasn't validating user input, causing a crash if
  something unexpected was entered.
* Was reseeding the random number generator in BigFixedPoint every time a new random
  number was requested. Other than being a waste, once I started seeding in Windows
  using milliseconds since epoch, I started to see the same number chosen twice in a
  row in the same question (i.e. 100 + 100, 42 + 42, etc). That should be fixed now.