Allow class:(class name) and style:(property-name)=(value) format

[Tal500]

Allow class:(class name) and style:(property-name)=(value) format, which is similar to Svelte class:(.) (although svelte doesn't support this style expression).

The style:(style_property)=(value) will update the HTML element using the DOM property element.style.style_property, which is cleaner and support legacy IE versions!

It will raise an exception in parsing time if both the new style:(.)=(.) format and the regular style=(.) is used, because it may conflict (and harder to set up in the JS DOM function).

Both of them will raise an exception in parsing time if the same property/class is defined twice for the same element.

This will have additionally the following advantages:

• Support conditional attribute scheme more easily.
• Better readability (sometimes)