warns on failed estimations
adds the vmatch script

The vmatch script can be used to compare the performance of andi with vmatch. The latter can compute indexes and matches which then can be used to compute the anchor distance. Since vmatch is much slower then andi this last step is skipped.
fixes warning being printed in any case
adds another warning
uses err.h instead of custom error messages
follow up commit
updates kseq.h

This fixes not only compiler warnings but also an issue when reading from pipes. See https://github.com/lh3/seqtk/pull/43 for details.
simplifies argument parsing
Merge branch 'master' of github.com:EvolBioInf/andi
adds random unit tests
fixes link for kseq.h
fixes manpage
Merge branch 'master' into ubuntu