Improve handling of restraints in the summary table

[aozalevsky]

Function get_restraints_info has to be refactored to:

1. avoid nonoptimal formatting:
   

   IHMValidation/master/pyext/src/validation/__init__.py

   Lines 514 to 519 in c3bb0ef

   	elif isinstance(i, ihm.restraint.PredictedContactRestraint):
   	restraints_comp['Restraint info'].append('Distance: '+str(i.distance.distance)
   	+ ' between residues ' +
   	str(i.resatom1.seq_id)
   	+ ' and ' + str(i.resatom2.seq_id))

2. update if-tree to support current him specs, for instance, ihm.restraint.PredictedContactRestraint can have multiple types ('lower bound', 'upper bound', 'lower upper bound').