Some forms of the access annotator.

Practically, for a pack that has been declared as ...T we have:

     T{N}     = access parameter at index N
     T{N,M}   = expand all parameters within [N,M) indices.
     T{N}...  = T{N,sizeof...(T)}

Some clarifications and analysis of the pattern interaction and then we
should be likely done releaving it from the interval annotator, which now
has a very straightforward meaning.
More access annotation clarifications!
Rules and syntax of annotation in a single section.

After removing equivalent form examples from syntax tables and clarified what
access annotation is all about, it becomes easier to express everything that
annotated template parameter packs are within a single, dense section. This
makes examples coming after less verbose to explain since the table can be
used as continuous reference.

Also, started deprecating the term "anchored" and "anchoring" over "access"
in expansion and single-expression "interval" in declaration. It needs a
little more care, but it is getting there. Issues #9, #10 are related.
Merging syntax table examples and accessors together.

Worked out syntax table examples so this is an easy merge.
Some fixes in the syntax table.

Let's remove what is "trivial to explain" because it would hurt the
explanation itself and explain it in simpler terms. Still some errors
are visible in the explanation of the text and table, should work
more on this.