updated readme
Merge pull request #12 from daitken/7.x

7.x grammar fixes
Add a couple functions to extract the version number.
Provide alternate image paths for older OpenSeadragon.

Addresses OnTime ticket 904. Also, update the README with a working
download link.
Use file_create_url() to avoid concatting manually.
Merge pull request #13 from adam-vessey/7.x

Address some version compatibility issues with the OpenSeadragon library.
Simplify version checks...

...  Probably should have poked around first.
Merge pull request #14 from adam-vessey/7.x

Simplify version checks...
Check the zoom levels to determine what dimensions the clip will be.
Rework based upon feedback.
Merge pull request #15 from jordandukart/7.x

Check the zoom levels to determine what dimensions the clip will be.
Changed Parameter Type Hinting to only use the top level Abstract class
Added Travis CI
Added dependencies for travis to run
Modified README to point to correct openseadragon address and fixed travis-ci
Fixed incorrect unzip path
Fixed travis-ci (hopefully)
Corrected link to Openseadragon download in README
Fixed code standards issues
Fixed coding standards issues.