fix project.resource

Per http://support.transifex.com/customer/portal/articles/1009524-resource-api

URL format is /project/<project_slug>/resource/<resource_slug>/ , with a singular "resource".
Merge pull request #1 from JasonBarnabe/fix-project-resource

fix project.resource
Merge remote-tracking branch 'upstream/master'
Add languages method
Add to README
Merge pull request #2 from JasonBarnabe/languages

Merge languages branch
Merge remote-tracking branch 'barnabe/master'