Statements

Thank you for creating this project as it fills, I think, a large gap in their website. I'm not much of a python'er but I wanted to grab all the statement PDFs from the site at the same time, just in case as it is their official record. I tried to be as close to the existing style as possible. Essentially all I changed was:

* Modified .gitignore to ignore all pyc
* Added `--statements` argument with a default to off
* Added `open_statements_page` function to grab HTML of the statements page
* On the statements page all statements have a class of `s_downloads` in their a tag so grab them
* Loop through all of them and save any missing ones to export as `28 Degrees Statement YYYY-MM-DD.pdf`
* Updated README.md to describe to users the new feature

Sorry if I'm doing anything wrong, this is my first time contributing to anything so this is all quite new to me. I hope this feature is of some use to you and everyone else!