Round calculated image sizes before concatenating cropper JS

Rounding to an integer ensures that we don't have problems with decimal-point
localization, which can produce JS parse errors.

Fixes #5245

Props olivM

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7571 cdf35c40-ae34-48e0-9cc9-0c9da1808c22