[WIP] Add Continuous Integration (CI) support

[Dr-Terrible]

This PR aims to:

• add Travis support to execute strict CI on the overlay;
• fix all the metadatas;
• upgrade all the ebuilds to EAPI6;
• fix all the warning/errors reported by repoman (except for copyright headers);

[Dr-Terrible]

@hasufell There are some packages that are already in Portage and sporting more recent versions; what am I supposed to do with them? Is it ok if I trim the old versions from this overlay?

[hasufell]

what am I supposed to do with them? Is it ok if I trim the old versions from this overlay?

I don't really care. Originally the idea was to make a games.eclass free overlay of ALL games. If the ebuild is the same as in portage, I guess one could drop it.

[Dr-Terrible]

@hasufell thank you for the answer; then I'll remove the redundant ebuilds, but only if the same packages in Portage don't make use of games.class. If a package from the Portage overlay is still using the games.eclass then I'll provide a PR to properly remove the deprecated eclass.

[hasufell]

No stable keywords in this overlay.

[hasufell]

Any progress here?