align detector comments to reality
define nets for pascal full-image classification by imagenet finetuning

CaffeNet definitions for pascal VOC image classification (not detection)
by finetuning the Caffe reference model for ImageNet.

20-way classification network (no background class).
add pascal class list for reference

(1 indexed to reserve 0 for background)
rename layers for finetuning (fc8: just finetune the classifier)