Sending to an alias and typing upper case characters leads to alias not valid

[Gigabyted]

Someone reported this to me, he said he was trying to send to an alias like this @Gigabyted and it wasn't letting him since it was @Gigabyted (lower case 'g')

I believe we should restrict to lower case chars (or convert them to lowercase as we type) if we set the leading char '@' that mark this as an alias.

Small issue but led to some issues between the 2 people that were trading...

[cryptozoidberg]

Fixed