resolves #706 output and style macro toc correctly

- alias toc2 attribute as toc=left
- deprecate all other uses of toc2 attribute
- allow toc placement to be specified using toc attribute
- only emit macro toc if toc-placement attribute has the value "macro"
- fix tests
- add matrix test for toc-related attribute values
Merge pull request #1051 from mojavelinux/issue-706

resolves #706 output and style macro toc correctly