Per-ring-buffer scaling of weights - Only currently works on fixed synapses
currently disabled saturation and lowered debug level
Plasticity code updated to handle per-ringbuffer scaling
Merge remote-tracking branch 'origin/merge_edges_pre_merge' into merge_edges

Conflicts:
	spynnaker/pyNN/models/abstract_models/abstract_population_data_spec.py
	spynnaker/pyNN/models/abstract_models/abstract_synaptic_manager.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/additive_weight_dependence.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/fixed_synapse_row_io.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/pfister_spike_triplet_rule.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/plastic_weight_synapse_row_io.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/spike_pair_rule.py
	spynnaker/pyNN/models/neural_properties/synapse_dynamics/stdp_mechanism.py
Small fixes and numpyifications of synaptic weight code
Small fixes and optimisation of examples
* Fixed c-code issues exposed by turning on DEBUG=DEBUG
* Fixed bug in synaptic row header length calculation for non-mad STDP
* Turned debug of ring-buffer scaling back off
* Parallelised the parameter sweeping of stdp_curve.py and stdp_triplet.py so they only take as long as the longest sweep