Add support for splitted zip archives in automatic analysis

[wfenrich]

No description provided.

[wfenrich]

It's very unconvenient that we only analyse files in *.zip archives, but at the same time we "softly" expect files to be of certain size (having in mind people, who will be downloading it later). We should allow users to easily split their archives with "zip -s", which, generates multiple files with *.z????... extensions, where "????...." stands for unspecified number of digits.