add "overwrite all" option to BEAST when log files exist. fixes #868
add "overwrite all" option to BEAST when log files exist. fixes #868

Anaphory/beast2,tgvaughan/beast2,tgvaughan/beast2,Anaphory/beast2,tgvaughan/beast2,CompEvol/beast2,CompEvol/beast2,Anaphory/beast2,tgvaughan/beast2,CompEvol/beast2,CompEvol/beast2,Anaphory/beast2