Removed list methods

Removed list methods for ContactTrace objects. When calculating
measures for several roots, the purpose is to use methods that
work directly on the data.frame with movements.

The following methods have been removed:
setMethod('OutgoingContactChain', signature(x = 'list'),...
setMethod('IngoingContactChain',  signature(x = 'list'),...
setMethod('InDegree', signature(x = 'list'),...
setMethod('OutDegree', signature(x = 'list'),...
setGeneric('NetworkStructure', signature = 'list',...
setGeneric('NetworkSummary', signature = 'list',...