increase packaged app max size to 100MB

https://bugzilla.mozilla.org/show_bug.cgi?id=958312

I tested this locally using cvan's junk file creation technique. The current tests change the max upload size to create a 1MB file instead of a 100MB file, that seems like a good idea.

    dd if=/dev/zero of=junk.zip bs=1024 count=102400