Fixed one bug of many in admesh library, where the face connectivity was broken when removing a degenerate face. Likely there are some similar issues left to be solved. Placed a workaround to always recalculate face connectivity before slicing.
a broken contour was not glued together using the closest neighbors.
Also the hash table size for admesh was made adaptive based on the number of faces.
The XS was left only for the unit / integration tests, and it links libslic3r only. No wxWidgets are allowed to be used from Perl starting from now.
