Return positive size for > 2gpx images, fixes #436
More Py_ssize_t changes
Merge pull request #437 from wiredfool/2gigapix-image

2gigapix image fixes
Add history
Prepare for 2.3.0 release in < 30 days
Fix manifest
Too many contributors to effectively list

This list was outdated so I'm removing it. At some point I'll do another pass
Fix travis