v3.7.3

Bugfix release to v3.7.2

Some updates to KGeoBag, KEMField, Kassiopeia. Notable:

• KEMField: fix behavior of number_of_bifurcations < 0
• KEMField: allow coaxiality_tolerance = 0 (disable coax. grouping)
• Kassiopeia: fix behavior of --config=file.xml on command line
• Kassiopeia: legacy field bindings (in <kassiopeia> tag) are now deprecated