ignore caffe generated files and stop ignoring examples

- ignore models and snapshots, means, and input databases
- excluding exceptions to commits is easier than including exhaustively
set examples paths relative to root
Merge pull request #1003 from shelhamer/examples-from-root

Standardize examples
[example] finetuning CaffeNet on Flickr Style data
[example] edit fine-tuning and train on ~2000 images, 1557 / 382 split

- further detail merits of fine-tuning: less starving for itme and data
- set random seed for reproducing the tutorial
- 1557 train / 382 test split is more indicative of training quality
  than splits of 200 images
Merge pull request #970 from sergeyk/dev

Fine-tuning tutorial: adapt CaffeNet to Flickr Style data
Solver switching support & implementation of Nesterov's accelerated gradient and AdaGrad
restored vituals in solver.hpp
converted pointers to shared_ptr
fixed solver constructor in train_net.cpp
improved numerical stability for AdaGrad
bugfixes for AdaGrad
Added L1 regularization support for the weights
fixed caffe.proto after a mistaken rebase
Addressed Yangqing's comments
fixes after rebase
proto conflit, lint, and math_functions (compiler complaint)
added unit test for solvers and fixed solver bugs
cleanup caffe.proto
Merge Test{SGD,AdaGrad,Nesterov}Solver; they become subclasses of
TestGradientBasedSolver