Mocha.jl v0.0.4

[Mocha.jl](https://github.com/pluskid/Mocha.jl) v0.0.4 release

## v0.0.4 2014.12.09

* Network
  * Parameter (l2-norm) constraints (@stokasto)
  * Random shuffling for HDF5 data layer
  * ConcatLayer
* Infrastructure
  * Momentum policy (@stokasto)
  * Save training statistics to file and plot tools (@stokasto)
  * Coffee breaks now have a coffee lounge
  * Auto detect whether CUDA kernel needs update
  * Stochastic Nesterov Accelerated Gradient Solver
  * Solver refactoring:
    * Behaviors for coffee breaks are simplified
    * Solver state variables like iteration now has clearer semantics
    * Support loading external pre-trained models for fine-tuning
  * Support explicit weight-sharing layers
  * Behaviors of layers taking multiple inputs made clear and unit-tested
  * Refactoring:
    * Removed the confusing `System` type
    * `CuDNNBackend` renamed to `GPUBackend`
    * Cleaned up `cuBLAS` API (@stokasto)
  * Layers are now organized by characterization properties
  * Robustness
    * Various explicit topology verifiecations for `Net` and unit tests
    * Increased unit test coverage for rare cases
  * Updated dependency to HDF5.jl 0.4.7
* Documentation
  * A new MNIST example using fully connected and dropout layers (@stokasto)
  * Reproducible MNIST results with fixed random seed (@stokasto)
  * Tweaked IJulia Notebook image classification example
  * Document for solvers and coffee breaks