Update ARM-2. Iteration to 0.2.0

This is a new, reworked version of the proposal. It uses the new
template and more clearly separates the recommended solution from the
alternatives.
Fix bad links to Expression Based Grammar.

Also adds an intro to Expression Based Grammar in the main document.
Fix header level issue.
Change to main index.
Update README.md
Update README.md
Update README.md
Make index a table.
Correct one example (missing an assignment).
Improve language in "Passing Lambdas in Calls"
Revise arm-2.iteration wrt. 'discussion', and 'uncompleted call'

Also fix typos, remove some duplicated text.
Update arm-2.iteration metadata and index.
Add technical description of ARM-11: Execution Model

I have not yet written the supplementary sections on testing/evaluation,
alternatives, etc, but I wanted to publish this more widely now that the
technical description is substantively complete so it could get wider exposure
and commentary.

Closes #26.
Fix erroneous mix-up of the link title vs description
Fix numbering in README. GRR.
Update JSON with accurate values