Add forced utf8 encoding of titles

Prevents yaml from binary encoding the title
Differentiates WordpressDotCom categories and tags

Since Jekyll front-matter supports categories and tags, I updated the
WordpressDotCom import script to set both of these.
Update usage documentation for manual RSS import
Merge pull request #35 from dlo/copy/rss-usage

Update usage documentation for manual RSS import
Update history to reflect merge of #35.
Add Travis build image to README.
Longer extnames :heart:
Be more verbose in the tumblr importer
Fall back to smaller photos if fetching one fails
Don't re-fetch photos
Save posts to disk immediately when not rewriting URLs
Ensure downloaded images are not of size zero.
Define Test::Unit::AssertionFailedError
Update dependencies in gemspec, notably requiring activesupport < 4.0.0
Bring in the big guns.
I hate active support.
Add importer for Google Reader blog exports
Update history to reflect merge of #27. Closes #27.
Merge pull request #22 from chrisivens/fix-drupal6-titles

Add forced utf8 encoding of titles
Update history to reflect merge of #22.