#110 add system properties and enviroment variable as sources

[gintau]

I add system properties and environment variable into sources. As suggested by @kevin-canadian, I use system:properties and system:env as their uri.

I suppose env vars are not updated during a process, so only system properties are hot-reloadable.

[lviggiano]

Hi. I've been off from this project since some time, I just noticed this pull request. I'll look into it asap.

[lviggiano]

I like the change you introduced, and I will merge it as soon as I verified why this build has failed on Oracle JDK 7:

https://travis-ci.org/lviggiano/owner/builds/56682901

Also we need some documentation to be added to show how to use it. There is a sub module that contains the website documentation here, and it is open to contributions: https://github.com/lviggiano/owner/tree/master/owner-site

You can add some lines to an existing page, or I will do it after I merge this change.

Thanks for your patience; and sorry for the delay. This long delay happens because I am having health issues that keeps me away from work and hobbies.

Luigi.