Description

add italy's demographics data (population grouped by age bins) on the city level
added pyshp package

Resolves #31

Checklist:

[x] I have read the CONTRIBUTING GUIDE and made sure this Pull Request is compliant with it.
[x] I have read the DATA MODEL and DATA SOURCES and made sure this Pull Request is compliant with it.
[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Any dependent changes have been merged and published in downstream modules