Inelegant use of lipsum text generator in Baconian cipher #37

PR #35 introduced the use of the lipsum crate. This works well and avoids the Baconian code bloating with boilerplate text constants.

However, currently, the usage is rather blunt, inelegant, as simply assigns lipsum text of an arbitrary 160 char length that may break if the plaintext is over ~50 chars in length.

Desired functionality: is that the default decoy text (generated using the lipsum crate) would automatically size to the length of the plaintext passed into the encrypt function.