Minor fixes.  (1) cudnn.hpp uses CHECK_EQ internally, so it needs to include glog at some point.  Including caffe/common.hpp.  (2) I often misconfigure some layer and softmax breaks when the dimensionality is too small for the input layers.  Check and fail fast.  (3) CV_LOAD_IMAGE_COLOR is deprecated and has been removed in OpenCV 3.0.  Replaced with cv::IMREAD_COLOR.
OpenCV should be compiled using pkg-config options.
Added version dependent test for IMREAD_COLOR.
Fixed CMakeList to work with OpenCV 3.
Merge pull request #1261 from kmatzen/minor_changes

[fix] build with OpenCV 3 and other minor fixes