Update coordinate_descent.py

Reverting _dense_fit to explicitly check precompute == True rather than just looking at its truthiness.

Should prevent unwanted precomputing, see https://github.com/scikit-learn/scikit-learn/issues/1734
Merge pull request #1736 from jamestwebber/patch-1

Update coordinate_descent.py
ENH set min_df in fe.text back to 1

2 is simply too confusing for users, since it causes trivial examples
to fail.
DOC improve mini-batch k-means narrative
COSMIT Moved the test_roc_curve_one_label test where other ROC curve tests are.
Merge pull request #1740 from tjanez/move_roc_curve_test

COSMIT Moved the test_roc_curve_one_label test where other ROC curve tests are
COSMIT pep8
DOC FIX links on grid search narrative
FIX numpy 1.3 issues with multilabel metrics
Update load_svmlight_file docstring.
Merge pull request #1741 from arjoly/metrics-fix-np-1.3

[MRG] FIX numpy 1.3 issues with the new multilabel metrics
TST compute_class_weight in utils
FIX + TST + DOC compute_class_weight

Fixes #1746, #1747. Bug reported and fix proposed by @gatagat.
ENH use bincount in compute_class_weight

As suggested by @amueller.
BUG use fixes.unique
FIX compute_class_weight edge case
BUG in SVM tests
FIX make_classification now outputs integer labels
DOC formatting (k_means)
BUG fix compute_class_weights issue in SGD

Fixes #1749.