List qt5 as a dependency

[mattheworres]

Great software, it worked the first time, and it was precisely what I was looking for, thank you so much!!

As a nice to have & make it easier for new users, you may want to list cmake and Qt5 as dependencies.

If this sounds amenable, I can put a PR in to "clean" up the README a little to help guide new users. Outside of debugging the CMAKE error around Qt5, this was a breeze in the park and I think a little guidance in the README will go a long way to helping more folks use this great package.

[edkb]

For anyone who went into this issue too, the following commands should fix:
sudo apt-get install qtbase5-dev
sudo apt-get install qtdeclarative5-dev