Fix the jobLimit of the imageLoader

I totally forgot about the issue #490 and fixed this now in the collections branch. I didn't want to fix it in master, since the structure is different (ImageLoader gets initialized in Drawer there) and so you would have to merge it.

**Update**
I just fixed another issue that has caused the imageLoaderLimit to not work, it wasn't incremented after starting a job.

Fixes #490
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