Minor clean-up

[memoryruins]

This PR utilizes std's impls for text_input and makes use of mem::take in the todo example.

[memoryruins]

Ah the life of only having nightly installed on this desktop has gotten the best of me; mem::take stabilizes in 1.40 🤦. In that case, we can use std::mem::replace(&mut self.text_input, String::default()) or I can revert that commit altogether.

[hecrj]

Thank you! These are nice changes! ❤️

I take note of from_iter and to_vec ✍️

[hecrj]

Awesome. Thank you! 🎉

[memoryruins]

Note to anyone looking in from the changelog: this could have been self.0.iter().collect() :)
_{micro-refactoring intensifies}