No empty lists, expanded descriptions in 5.1
closes #230; goes green; improves json property descriptions
Merge pull request #235 from IIIF/empty_lists

Empty lists
Update links to Mirador demo site
Merge pull request #239 from IIIF/mirador-link-update

Update links to Mirador demo site
No keepalive in .htaccess in 2.2. closes #241
Merge pull request #242 from IIIF/nokeepalive

No keepalive in .htaccess in 2.2. closes #241
service changes re phys dims

Made services available to Image API, redescribed physical dimensions to work for PPI. Closes #220

Changelog entry for services in Image API

Greening; remove link to deleted 5.2 extensions
Rebased from master