fix grammar in comment

migth -> might
want -> wants
Implement progressive loading of PDFs
Merge pull request #3089 from terrafrost/master

grammar fix for some comments
Changes to regression tests for progressive loading
Make getOperatorList() calls independent and merge queues at end
Address brendan's comments
Address more of brendan's comments
Merge pull request #2719 from mduan/chunked

Implement progressive loading of PDFs