Missing tags

[martinthomson]

I just ran the tool and it produces a lot of warnings about unsupported tags. This is a list of the ones I found:

• table
• iref
• aside
• sup
• contact
• tt
• name
• reference
• references

Some of these likely require a bunch of work (tables, for instance). Others should be simple enough to turn into text directly (contact, iref, sup, tt). Some might just be ignored (aside, reference, references).