Add --no-self option

[iimog]

alitv.pl by default calculates all-vs-all genome alignments this includes a comparison of each genome against itself. This information is currently not visualized in the AliTV frontend. It might be useful to do this in the future but right now this behavior just increases calculation times and the size of the output file without any benefit. Therefore I'd suggest disabling self alignments by default and adding a parameter to re-enable them if wanted.