change "username" textbox in login scene to "email" textbox

parts/scenes/login.lua

@@ -1,14 +1,14 @@
 function keyDown.login(key)
 	if key=="return"then
-		local username=	WIDGET.active.username.value
+		local email=	WIDGET.active.email.value
 		local password=	WIDGET.active.password.value
-		if #username==0 then
-			LOG.print(text.noUsername)return
+		if #email==0 or not email:match("^[a-zA-Z0-9_]+@[a-zA-Z0-9_-]+%.[a-zA-Z0-9_]+$") then
+			LOG.print(text.wrongEmail)return
 		elseif #password==0 then
 			LOG.print(text.noPassword)return
 		end
 		local success,data=json.encode({
-			username=username,
+			email=email,
 			password=password,
 		})
 		if not success then
@@ -32,7 +32,7 @@ end
 WIDGET.init("login",{
 	WIDGET.newText{name="title",		x=80,	y=50,font=70,align="L"},
 	WIDGET.newButton{name="register",	x=1140,	y=100,w=170,h=80,color="green",code=function()SCN.swapTo("register","swipeR")end},
-	WIDGET.newTextBox{name="username",	x=380,	y=200,w=500,h=60,regex="[0-9A-Za-z_]"},
+	WIDGET.newTextBox{name="email",		x=380,	y=200,w=500,h=60,regex="[0-9A-Za-z@._-]"},
 	WIDGET.newTextBox{name="password",	x=380,	y=300,w=626,h=60,secret=true,regex="[ -~]"},
 	WIDGET.newButton{name="back",		x=1140,	y=640,w=170,h=80,font=40,code=WIDGET.lnk_BACK},
 })