disable the seed filter when using short kmers

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
add a maximum coverage depth for dead end search

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
adapt the allowed depth in function of the data

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>