test11 :: check if we can repair the exaclty 5% removed data

Signed-off-by: BlackEagle <ike.devolder@gmail.com>
par2creator :: rework blocksize algorithm when blockcount is given

this fixes #21

there was a fix attached to the original bugreport
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=655334
but thatone could lead to a blockcount of 0 which lead to a SEGV

Signed-off-by: BlackEagle <ike.devolder@gmail.com>