[python] move magnitude to geometry

Closes #14

See merge request tools/frackit!157

[python] move intersections to geometry module

See merge request tools/frackit!156

Feature/python move empty isection

See merge request tools/frackit!155

Feature/move python brep wrappers

See merge request tools/frackit!154

OCCCompundWrapper is default constructible, which makes this
construction function obsolete.

Feature/python boundary distance

See merge request tools/frackit!153

[python][isect][poly-disk] fix registry

See merge request tools/frackit!152

Feature/polygon disk intersection

See merge request tools/frackit!150

[test][box] do not check  volume equality

See merge request tools/frackit!149

Feature/python distance bindings

See merge request tools/frackit!148

Feature/python intersections

See merge request tools/frackit!147