Look for plugins under the source directory

When generating the site, Jekyll will now look for plugins under the
source directory by default. The plugin location can still be changed in
_config.yml
Merge remote-tracking branch 'upstream/master' into issue-653
Look for plugins under the source directory by default
Add TomDoc
Merge branch 'master' into issue-653
first pass at --drafts flag
fix tests
add drafts.feature
Improve error message for malformed highlight tags
fix whitespace in drafts.feature
Allow symlinked folders in unsafe mode
Now uses the more semantically correct AND operator
Don't require date in draft filenames.
implement and use Draft.valid?
don't mess with dir parameter
fix draft filename processing
don't check if draft is published or if its date is in the future
whitespace fixes
Merge branch 'master' into issue-653
Add back a test that was mistakenly removed.