resolve #1 - add templates for AsciiDoc processing instructions

- templates for AsciiDoc pis (line break, page break, rule)
- add asciidoc.mode to tune defaults when using AsciiDoc output
- set defaults for toc and numbered based on AsciiDoc pis when asciidoc.mode = 1
- use toc settings from AsciiDoc distro when asciidoc.mode = 1
- fix inlinemediaimage to behave as an inline element
- add CSS for page break