Bug summary when building caffe in Ubuntu 16.04

## pycaffe installation problems
# bug1
>>> import caffe
ImportError: /home/../anaconda2/lib/python2.7/site-packages/zmq/backend/cython/../../../../.././libstdc++.so.6: versionGLIBCXX_3.4.21' not found (required by ../python/caffe/_caffe.so)`
>>> quit()
# solution
$ conda install libgcc

# bug2
ImportError: No module named google.protobuf.internal
# solution
$ pip install protobuf
$ /home/username/anaconda2/bin/pip install protobuf