Make comparison of extensions in zip addition case insensitive.
Make logic more concise.
Use format_plural(), 'cause it's awesome.
Get rid of explicit batch_process() call, and avoid dividing by zero...

... Don't run the batch if there are no files to add in the ZIP file.
Coding standards... squash some whitespace.
Added jp2 as an acceptable file extension on batch process.
Merge pull request #100 from adam-vessey/7.x-case-sensitivity

Make extensions case insensitive, and a bit of misc cleanup.
Fixed merge conflict.
Reverted to cc7d8cb3bcd76e32fa2c22b89c2d282f56d7793b
Added jp2 as acceptable file extension
Updated islandora_pageCModel_ds_composite_model.xml with the image/jp2 mimetype.
Merge pull request #102 from MorganDawe/7.x

Added jp2 as acceptable file extension
merged Morgan's changes