Support for Markdown

[ghaiklor]

It is hard to use Builder pattern if you want to create an enormous deck with a lot of slides, too much code. So we should support a way to write slides in Markdown, parse it and build a Deck from it automatically.

It will remove a lot of flexibility, but we gain a lot easier way to create slides.

So there should be two ways to create a deck:

• Through Builder pattern if you want to have a lot of flexibility, like custom positioning on the canvas, your own animations, etc...
• Through Markdown if you don't care about flexiblity, but about easier slide creation