Merge pull request #253 from zimeon/implementation_notes_2

Adjust region/size calculation to use ceil rounding, add algoritm for rotation size calculation
Adds a blank index.html page at api/presentation/1.0/index.html to keep Travis happy
Merge pull request #255 from IIIF/fix_prezi_blank_page

Make  api/presentation/1.0/index.html
Pin gems to known working versions. Jekyll 2.1.0 seems to be a problem.
Merge pull request #256 from IIIF/pin_versions

Pin gems to working versions