整理代码，新增string扩展模块，把一些小模块合并进string和table扩展模块中

parts/scenes/login.lua

@@ -1,7 +1,7 @@
 local function login()
 	local email=	WIDGET.active.email.value
 	local password=	WIDGET.active.password.value
-	if not legalEmail(email)then
+	if not STRING.simpEmailCheck(email)then
 		LOG.print(text.wrongEmail)return
 	elseif #password==0 then
 		LOG.print(text.noPassword)return