Revert "Change the default link distance of pano"
Revert "Change the default link distance of pano"

Because of a serious bug

This reverts commit ae908701b90543e19e6efeb2cdaeac44c78fc8f3.

igemsoftware2016/USTC-Software-2016,igemsoftware2016/USTC-Software-2016,igemsoftware2016/USTC-Software-2016