Add a small part about cross-validation + copyedit

Don't bother newbies with "linear kernels, or the lack thereof"
(maybe refer to an ML/SVMs textbook?)
Copyedit on the "working with text" chapter
Merged pull request #5 from larsmans/master.

Some more copyediting, as well as a small section on cross-validation
Text chapter: load_files renamed load_filenames

Name was changed in scikit-learn commit 5b806e
Merge branch 'master' of github.com:scikit-learn/scikit-learn-tutorial
Revised text classification chapter

* Expanded narrative in several sections
* Show convenient fit_transform before separate fit and transform
* Show multinomial NB first, then linear SVM
* Don't bother user with mysterious parameters until grid search section
* Copyediting

I've assumed novice users interested in NLP and related stuff will check
this chapter first, so I've tried to make it more or less self-contained.
Copyright and project name in HTML footer

Formerly:
    This documentation is relative to scikit-learn tutorial version 0.1
Now:
    This tutorial is for scikit-learn version X.Y
where X.Y is the scikit-learn version.
Merge pull request #6 from larsmans/master

Revised text classification chapter
add the test command
Updated README
Remove ugly BLANKLINE stuff from text chapter
Use grid_scores_ instead of _get_params + small fixes in text chapter
update doctest in tutorial to match current API
fix the random state of the files dataset loader for reproducible results
Upgrade the setup documentation to match the current master
updated README.md
fixed left-over of the previous version
more details for poor windowsians
upgrade to simpler new load_file API
s/class_names/target_names/g