Add the brown frog image, cuz its a little bit my favourite!
Move supplementary files into docs dir

To avoid spamming toplevel dir
Remove old comment

I checked it on Windows, it worked fine
Bump dependency on parser to 2.0.0
Wrap pending blocks around the not implemented features

So you can run `rspec` without failures
Add the value of matrix_filename to make it clearer to readers
Some simple cleanups
Bump version to 2.0.4

Biggest change is the dependency update on Parser