wtf?

This bug was introduced when line breaks mid-verse were introduced,
resulting in double line breaks at the end of all verses.

The function would never panic when an invalid URL was pssed in.
Instead, it would simply return and invalid path.
For example, if you passed in `https://google.com`,
it would return `google.com`.

This rewrites the method to instead correctly return an empty string if
an invalid URL is passed in.

Closes #42.

Windows builds don't use cross, so don't bother installing it.

Swatinem/rust-cache caches installed binaries. Setting it up before
installing cross lets us take advantage of that.

The default and maximum sizes now match the source image, but limited to
1000 to prevent potential abuse.

This fixes the "View on Genius" text being mostly cut off on mobile