Merge pull request #416 from xdanielsb/doc-formats

Update doc, clarify the use and scope of the flag headers.

AUTHORS

@@ -8,6 +8,7 @@ Here is a list of passed and present much-appreciated contributors:
     Benjamin Wohlwend
     Bruno Soares
     Claude Paroz
+    Daniel Santos
     Erik Youngren
     Hugo van Kemenade
     Iuri de Silvio

docs/tutorial.rst

@@ -110,6 +110,12 @@ Creating a :class:`tablib.Dataset` object by importing a pre-existing file is si
 
 This detects what sort of data is being passed in, and uses an appropriate formatter to do the import. So you can import from a variety of different file types.
 
+.. admonition::
+
+    When the format is :class:`csv <Dataset.csv>`, :class:`tsv <Dataset.tsv>`, :class:`dbf <Dataset.dbf>`, :class:`xls <Dataset.xls>` or :class:`xlsx <Dataset.xlsx>`, and the data source does not have headers, the import should be done as follows ::
+
+    imported_data = Dataset().load(open('data.csv').read(), headers=False)
+
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 Exporting Data
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