Fix possible warnings with node checks.
Fix possible warnings
Add creators property.

Iterates through the creators node and returns tuples of
(name, role) pairs.
Fix possible warning from if check.
Add editorial_reviews which returns a list of editorials.

editorial_review returns the first review.
Add test for single and multiple editorials.
Add check for None and fix possible warning.
Add languages property.

Iterates through ItemAttributes.Languages and pulls out the
Language.Name text values.
Add tests for english and spanish books.
Add a docstring for creators property.
Merge pull request #34 from adamlwgriffiths/warnings

Fix a few lxml warnings and potential errors.
Merge pull request #35 from adamlwgriffiths/creators

Add creators property
Merge branch 'editorials' of github.com:adamlwgriffiths/python-amazon-simple-product-api into adamlwgriffiths-editorials

Conflicts:
	tests.py
Merge branch 'adamlwgriffiths-editorials'
Merge branch 'languages' of github.com:adamlwgriffiths/python-amazon-simple-product-api into adamlwgriffiths-languages

Conflicts:
	tests.py
Merge branch 'adamlwgriffiths-languages'