Enable filtering cells touching borders

[lguerard]

python-imcflibs/src/imcflibs/imagej/objects3d.py

Line 74 in 26f64c9

def segment_3d_image(imp, title=None, min_thresh=1, min_vol=None, max_vol=None):

doesn't have an argument to automatically remove cells touching borders, this could be added.

[ehrenfeu]

Since #139 got merged this should be complete, correct? Please re-open if not...