Some small enhancements for merged commit

- Spelling
- Check on document state
- Checkin works with set_versioning_state
Improve documentation
Regenerate gemspec for version 0.3.4
Add some spaces at end of lines in README
Fix issues with checkin

I really need to start adding tests, these changes were tested against
Alfresco (but without any content to the document, so who knows what
broke there)
Closes #23
Version bump to 0.3.5
Regenerate gemspec for version 0.3.5
Merge remote-tracking branch 'upstream/master'
Allows you to set the HTTP timeout