infer: fixing assorted bugs which prevented MPLP from being useful for training
New classes DenseTensorProportions{1,2,3,4} are Proportions which also inherit from DenseTensor.  Useful for use in gradients because they will match in +=, dot, etc.
Fix some comments that succumbed to Tensors->WeightsMap substitution.
Further twiddling with NER3.
Merge.
app.chain.Observation: Make addNeighboringFeatureConjunctions not look beyond the input sequence; e.g. if given sentence.tokens, do not use incorporate features from token.next beyond the sentence.
la: DoubleSeq no longer defines foreachActiveElements; many bugs caught
merge
New Proportions that are DenseTensors and SparseIndexedTensors.  Not yet compiling, but Alex will fix next.
Merge.
la: fixing the tensor proportions