initial commit: The OrbTK book source tree

All files have a strong relation to the book sources of the
rust-lang project itself. This may help to lower the burden
for intrested people to get involved in OrbTK as well as
reuse workflow habits.

* LICENSE-MIT: The projekt licensing terms
* README.md: Github frontpage
* CONTIRBUTING.md: Advises on howto help improving the book
* style-guide.md: Advises on howto improve the readability of
  generated prose and code.
* tools: layout helper scripts and rust-code
* ci: continius integration helper scripts
* .gitattributes: set git default behaviours
* .gitignore: keep source tree sane
* Cargo.toml: package dependencies
* rustfmt.toml: formatting rules for rust code
* book.toml: mdBook dependencies

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

CONTRIBUTING.md

@@ -0,0 +1,43 @@
+# Contributing
+
+We'd love your help! Thanks for caring about the book.
+
+## Licensing
+
+This repository is under the same license as OrbTK itself, MIT. You
+can find the full text the license in the `LICENSE-MIT` file in this
+repository.
+
+## Code of Conduct
+
+The OrbTK project has [a code of conduct](https://github.com/redox-os/orbtk/policies/code-of-conduct)
+that is in line with the one used in the RUST Projekt itself. It governs all sub-projects,
+including this one. Please respect it!
+
+## Review
+
+Our [open pull requests][pulls] are new chapters or edits that we're
+currently working on. We would love if you would read through those and make
+comments for any suggestions or corrections!
+
+[pulls]: https://github.com/orbtk/book/pulls
+
+## Help wanted
+
+If you're looking for ways to help that don't involve large amounts of
+reading or writing, check out the [open issues with the E-help-wanted
+label][help-wanted]. These might be small fixes to the text, OrbTK code,
+or shell scripts that would help us be more efficient or enhance the book in
+some way!
+
+[help-wanted]: https://github.com/redox-os/orbtk/book/issues?q=is%3Aopen+is%3Aissue+label%3AE-help-wanted
+
+## Translations
+
+We'd love help translating the book! See the [Translations] label to join in
+efforts that are currently in progress. Open a new issue to start working on
+a new language! We're waiting on [mdbook support] for multiple languages
+before we merge any in, but feel free to start!
+
+[Translations]: https://github.com/redox-os/orbtk/book/issues?q=is%3Aopen+is%3Aissue+label%3ATranslations
+[mdbook support]: https://github.com/rust-lang-nursery/mdBook/issues/5