Comment support and single tag support

[mjkaufer]

Stuff like <!--comment--> should have a jsml equivalent. Also, we should check for things like <br/> should be coded for in jsml as, currently, the jsml would output as <br></br>.

[phikal]

When

{
t:"br"
}

is used

<br/>

Should come out.

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Maybe a Type tag should be implemented, default being HTML and a first addition Comments?