Merge pull request #245 from gregquat/master

adding cookbook/forms/use_empty_data.rst file
Update introduction.rst

Duplicate entry
Merge pull request #246 from ErikSaunier/patch-2

Update introduction.rst
updating some sections in book/form
extra word
Merge pull request #247 from bamarni/patch-1

extra word
First part of update translate of References

Add a custom .gitignore
Some ommissions

and not translate file
Merge pull request #248 from StefTweet/master

First Part of translate and update of references sections.
Translate missing sentence
Updating some sections in book/form
Merge remote-tracking branch 'originale/master'
Ending review of book/form
review of Reference/form/types/options/*