Preseed mutations

[aoh]

Some mutations (e.g. fuse old) need some information about data elsewhere in order to work properly on the first run. As a result, simple and likely common usage patterns such as $ while true; do radamsa samples/* | tee testcase | timeout 10 target - || break; done will never make many useful changes.

Radamsa should preseed these mutations with one or more data blocks. This would be trivial if radamsa wasn't required to be deterministic whether the sample data comes from a file or a pipe.

Anyway, it sucks, so it should be solved.