Raise exception for sparse inputs in the case of svd solver

Fixes #3709, #3718.
Rename k to n_clusters in docs
Merge pull request #3724 from mlopezantequera/patch-1

Rename k to n_clusters in docs
MAINT use Python versions provided by AppVeyor CI
FIX call srand whenever random_seed >= 0 in libsvm

This bug was discovered by #3691 (failing test under windows).
Enable grid search with classifiers that may throw an error on individual fits.
Fix sparse_cg solver when max_iter is specified.
Merge pull request #3730 from ogrisel/fix-libsvm-random-seed

[MRG+1] FIX call srand whenever random_seed >= 0 in libsvm
MAINT missing numpy / scipy for the Python 3.3 build

Building scikit-learn on Python 3.3 on appveyor would first require
building numpy and scipy wheels.

Disabling in the mean time.
+ Fix a typo.
plot_adaboost_twoclass.py: minor improvements
Merge pull request #3731 from ndawe/master

plot_adaboost_twoclass.py: minor improvements
Merge pull request #3732 from queqichao/fix_typo

Fix a typo.
Changed default argument of precompute in ElasticNet and Lasso

Setting precompute to "auto" was found to be slower when n_samples > n_features
since the computation of the Gram matrix is computationally expensive and
outweighs the benefit of fitting the Gram for just one alpha.
TST: Added tests to test Deprecation warning
DOC on negation of loss functions used as scoring parameters

+ copy editing to model evaluation narrative documentation
DOC reduce table width through less-qualified function names
[WIP] Choose out of bag scoring metric. Fixes #3455
Provide prediction probabilities and decision function to scorer.
Move oob_score out of forest, add get_score w/ refactoring.