kernel_ridge.py

* addressed comments in the PR about parameters in check_array

* update the test case for the evaluation of estimators with pandas series

* bug fix, need to check for *not* None explicitly

* updated with isinstance check if the documentation says there is acceptance of floats

* ran pep8 linter on modified files

* moving the test case to estimators_check

* add a predict function into the testing pandas.Series class

* avoid running anything beyond the newly added meta checks

* check if pandas is installed before running the specific test

* changed the order of the try-catch to check for sample_weight param beforehand

* pass on import error rather than printing something to std out

* improve test case naming and pd.Series check in the bad estimator class

* address a pep8 linter error with unused import

* pep8 warning disabled for potential unused import

* throw a warning when SkipTest is raised

* add a SkipTestWarning

* updated the whats_new.rst with this issue

* rebase and fix a spacing issue