Merge pull request #3 from julian-upc/master

Updating
new file
added code for sheet3
Create README
sheet3
Merge pull request #118 from aitor-perez/master

added code for sheet3
Merge pull request #117 from arnauplanas/master

sheet3: code, readme and diary
Merge pull request #119 from Gwenaelaurent/master

sheet3
Merge pull request #12 from julian-upc/master

actualitzar