Add detailed error reporting to the ZEC send UI

[pacu]

Is your feature request related to a problem? Please describe.

The user can provide bad input to the ZEC send form

Describe the solution you'd like

The send ZEC screen should provide good feedback to the user about errors on the form input.

• Amount too small (cannot cover fee)
• Amount too large (exceeds current balance)
• Bad address

[daira]

Amount too small (cannot cover fee)

Does that imply that the fee is deducted from the amount entered? That seems not a good UI to have by default: normally, I want to guarantee that the recipient will get the amount of money I enter.

[nuttycom]

This may be related to Electric-Coin-Company/zashi#39 and Electric-Coin-Company/zashi#40

[LukasKorba]

Closing as done