Turn off XLS output if number of written rows exceeds MAX_ROWS
Small fixes
If there is an error don't write the XLS(X) file.
Added comment
Fail style.
More stuff added to .gitignore.
Add "failed" as a state.
Create error message and store it in database, when writing too many rows.
Update default file to xlsx in reset_downloads.py.
Don't set error when stopping writing XLS file because it's too big.
Merge pull request #56 from scraperwiki/add-max-rows

Turn off XLS output if number of written rows exceeds MAX_ROWS