Ability to have a dynamic amount of i/o conections on a node.

[TimZaman]

This is needed for caffe.
For example the 'Accuracy' node needs input data and a label as reference. These are two input connections, that need to go to input ports [0] and [1] repectively. This might be problematic to obtain.

From a caffe point of view, this is easy to obtain if this can be solved: BVLC/caffe#4712 . If this cannot be solved, I will have to crawl through the caffe code and obtain and input all the top and bottom i/o's by hand. This will also mess up the dynamic .proto parsing, as I will add things that are static.. sigh..