Foliantcontrib-includes

- Support Foliant 1.0.9. Add processing of `!path`, `!project_path`, and `!rel_path` modifiers (i.e. YAML tags) in attribute values of pseudo-XML tags inside the included content. Replace the values that preceded by these modifiers with absolute paths resolved depending on current context.
- Allow to specify the top-level (“root”) directory of Foliant project that the included file belongs to, with optional `project_root` attribute of the `<include>` tag. This can be necessary to resolve the `!path` and the `!project_path` modifiers in the included content correctly.
- Allow to specify all necessary parameters of each include statement as attribute values of pseudo-XML tags. Keep legacy syntax for backward compatibility.
- Update README.

- Take into account the results of work of preprocessors that may be applied before includes within a single Foliant project. Rewrite the currently processed Markdown file path with the path of corresponding file that is located inside the project source directory *only* if the currently processed Markdown file is located inside the temporary working directory *and* the included file is located outside the temporary working directory. Keep all paths unchanged in all other cases.

- Do not rewrite source Markdown file if an error occurs.

- Don’t crash on failed repo sync (i.e. when you’re offline).

- Require at least one space after hashes in the beginning of each heading.
- Add `inline` option to the `<include>` tag.
- Fix the bug: do not ignore empty lines after headings when using `sethead`.
- Fix the bug: allow to use less than 3 characters in the heading content.
- Do not mark as headings the strings that contain more than 6 leading hashes. If shifted heading level is more than 6, mark the heading content as bold paragraph text, not as heading.

- Fix paths resolving in case of recursive processing of include statements.
- Allow revision markers in repo aliases.