Add (momentum) SGD solver tests to check that learning rate, weight decay, and momentum are implemented properly on a least squares problem.
Add (momentum) SGD solver tests to check that learning rate, weight
decay, and momentum are implemented properly on a least squares problem.

CZCV/s-dilation-caffe,tackgeun/caffe,gnina/gnina,wangg12/caffe,gogartom/caffe-textmaps,longjon/caffe,gogartom/caffe-textmaps,wangg12/caffe,wangg12/caffe,wangg12/caffe,CZCV/s-dilation-caffe,gnina/gnina,CZCV/s-dilation-caffe,gogartom/caffe-textmaps,gnina/gnina,tackgeun/caffe,longjon/caffe,tackgeun/caffe,longjon/caffe,tackgeun/caffe,gnina/gnina,CZCV/s-dilation-caffe,gogartom/caffe-textmaps,gnina/gnina,gnina/gnina,longjon/caffe