Backward compatibility of talk formats.

- 40' and 20' formats availability accordingly to the edition
- filtering based on available formats
- gitignore
v2.1.1
Merge pull request #6 from sudweb/fix-oldspreadsheets

Fix old spreadsheets talk formats
Merge branch 'master' into gh-pages

* master:
  v2.1.1
  Backward compatibility of talk formats.