[mlpack] mlpack 3.1.1 released

[Ryan Curtin]

Hello everyone,

I hope your weekend has gone well!  Today I tagged mlpack version 3.1.1
and it is now released.  (The Windows installer will be updated on the
website once the AppVeyor build succeeds.)

Here is a changelog:

  * Fix random forest bug for numerical-only data (#1887).

  * Significant speedups for random forest (#1887).

  * Random forest now has `minimum_gain_split` and `subspace_dim`
    parameters (#1887).

  * Decision tree parameter `print_training_error` deprecated in favor
    of `print_training_accuracy`.

  * `output` option changed to `predictions` for adaboost and perceptron
    binding. Old options are now deprecated and will be preserved until
    mlpack 4.0.0 (#1882).

  * Concatenated ReLU layer (#1843).

  * Accelerate NormalizeLabels function using hashing instead of linear
    search (see `src/mlpack/core/data/normalize_labels_impl.hpp`)
    (#1780).

  * Add `ConfusionMatrix()` function for checking performance of
    classifiers (#1798).

  * Install ensmallen headers when it is downloaded during build
    (#1900).

Since the releases are now mostly automated (saving me lots of hours),
there isn't too much else to write! :)

More information here:

https://github.com/mlpack/mlpack/releases/tag/mlpack-3.1.1

As always, feel free to get in touch on IRC or Github or on this email
list if you have any issues and we'll do our best to address them.

Have a great week!  (And also the GSoC coding period starts tomorrow, so
that should help make it a great week. :)  I am excited to see all the
things that will happen this summer.)

Ryan

-- 
Ryan Curtin    | "How long have you had these things on?"
ryan at ratml.org | "Sixty-two years."