[pycaffe] expose Net::CopyTrainedLayersFrom as Net.copy_from

This allows finetuning from Python, for example.
[pycaffe] expose Net::SharedTrainedLayersWith as Net.share_with
Merge pull request #1195 from longjon/python-copy-from

Expose Net.copy_from and Net.share_with in pycaffe
fix instantiation
adding missing libraries - lm and lstdc++
Merge pull request #1258 from Yangqing/instantiation

fix instantiation per C++ standard
A running ReshapeLayer; not much testing yet.
Lint fixes (mostly whitespace).
Tests for ReshapeLayer, checking whether we can flatten the output.
Following the numpy convention with -1 for "infer", 0 for "copy".

(In ReshapeLayer target dimensions.)
Additional tests for -1 and 0 as ReshapeLayer output dimensions.