[v6] Add data attributes in Messages

Added data attributes to messages.

var message_data = {
    text:"hello framework7",
var add_message = messages.addMessage(message_data)

Added messages↓

<div 0="d" 1="a" 2="t" 3="a" 4="-" 5="i" 6="d" 7="=" 8="" "="" 9="1" 10="" class="message message-sent test_message message-appear-from-bottom message-first message-last message-tail">
    <div class="message-content">
        <div class="message-name">alice</div>
        <div class="message-bubble">
            <div class="message-text">hello framework7</div>

The attrs array will be added one character at a time.
Is there any way to improve this?

I confirm the very same issue.
Looks like a bug.

Please note, that it takes characters from the attribute name and puts them as a value. And the resulting attribute is an index of the character in the original attribute name.