Merge pull request #186 from dcamarmas/master

4.1: calculator minor update

Merge pull request #158 from dcamarmas/master

4.0: minor update

Merge pull request #131 from dcamarmas/master

3.2.1

Merge pull request #122 from dcamarmas/master

3.1: minor update

3.0: minor update

Merge pull request #77 from acaldero/master

2.1.0: minor updates

Merge pull request #38 from dcamarmas/master

1.3