readme: General cleanup; see more below.

* Use Unix instead of Windows newlines.
* Update godoc URL.
* Consistent use of 4 spaces instead of tabs.
* Minor reformulations.
* Use `go get` for installation and `cp` for configuration.

NOTES

* Do you think we should remove the security section?
strip: Add code review comments.
strip: Add additional review comments.
settings: Add review comments.
page: Add review comments.
mail: Add review comments.
ini: Add review comments for test cases. reflect.DeepEqual cleans up a lot.
ini: Add review comments.
filename: Add review comments.
distance: Add review comment.
cli: Add review comments.
cmd/nyfikenc: Add review comments.
cmd/nyfikend: Add review comments.