(feature request) - Shielded memo character count

[lightnode]

Summary

A user doesn't know when they have exceeded the character limit in a shielded memo until after they press 'Send'. Doubly annoying is all fields are wiped upon return--including the memo!

Suggesting:

1. A Twitter-style character counter (including the red highlighted text when exceeding the limit)
2. Should a user go over the limit and still press 'Send', have the data in the To, From, Amount and Memo fields persist
3. Improve the Error copy to be more friendly. Something akin to: "Whoops! You've exceeded the maximum character limit in your memo. Please edit and try again. 🙂")