Add Travis CI configuration.

Fixes #99.
Add Travis CI badge to README.
Add tests for special characters in mentions.
Mentions now stop at first non word character.

Fixes #101.
Merge pull request #100 from mvitz/travis-support

Add Travis CI configuration.
Merge pull request #102 from mvitz/fix-special-signs-in-mentions

Fix special signs in mentions.
Add missing patterns and reordered gitignore.

- .lein-repl-history exists after running lein repl
- .nrepl-port exists while running lein repl
- .lein-failures exists after running lein test
- order is taken from: https://www.gitignore.io/api/clojure
Fix generated HTML of navigation box.

Instead of something like ```<li>Section<li>Link</li></li>``` now
```<li>Section</li><li>Link</li>``` is generated.
Add client side opt in for image inlining.

Refers to #92.

Currently to preserve behaviour image inling is turned on by default and
the user has no option to disable it. This will be added later.
Extract methods for navigation sections.

This allows adding new sections which contains other items than simple
links.
Add preference section to navigation box.

Fixes #92.

This enables the user to opt in for image inlining. By default image
inlining is disabled.