Deprecate ReadNeuronFromAM
don't check for NeuronName
Deprecate ReadNeuronFromSWC, WriteSWCFile, ParseSWC, WriteSWCFile
Rm testParseSWCTreeEquivalent - methods are equivalent both will be replaced
Teach DotPropertiesFromFile to get points from any neuron & cut ReadSWCFile
deprecate WriteNeuronToAM3D
Deprecate WriteNeuronToAM (-> nat)
Fix ignored Force argument in WriteNeuronToAM3D
read.neuron -> read.neuron.extra and register it as a fall-through reader

* this way it will be called by nat::read.neuron if all else fails
write.neuron -> write.neuron.extra (asc and Borst ftypes only)

* nat::write.neuron does all the types we care about these days
Signal that write.neuronlist is deprecated - but don't convert to wrapper yet
fix a couple of overzealous tests
remove all old code for reading neurons in Amira formats

* has been superseded by nat::read.neuron and the functions it wraps
remove direct references to ReadNeuronFromAM3D
Don't test SingleFromDoubleEdgeList and ParseEdgeList since part of graph-based parsing