Bump version to 2.4.1

Before http://infinite-labs.net/afloat/ redirected to the GitHub page, I had downloaded the latest version from there.
That version was 2.4 (I know that 2.3 is the latest version from the GitHub page).

This makes sure that the version is greater than that.
Merge pull request #1 from Tyilo/patch-1

Bump version to 2.4.1