"Amount" fields are accepting the letter E as valid input

[rafaeldjpbrochado]

Issue description

When sending funds, I tried to write a string in the Amount field and none of the alphabet characters showed up there except for when I pressed the letter e.

Wallet version

v0.1.0

System specification

Windows 10.

Is it a repeatable issue?

Yes.

Steps to reproduce the issue

1. Press Send Funds
2. Type "e" in the Amount field

Expected behavior

I expected the Amount field to only accept numbers. No letters or special characters.

Actual behavior

eeeee

[rafaeldjpbrochado]

Seems like you can also add + and - signs in there.

[obany]

Should be fixed with this PR #481 please reopen if still broken after next build is released