Markdown Feature requests

[CeJienAJPC]

This library is working great. I would like to request, for the addition of following features. They might be helpful to many (not sure if everything would be possible, though).

• Text Sizes like Small, Medium, Large or in Font Sizes
• Text Color
• Youtube Video
• GIF
• Tweet

Thanks again for this nice library.

[tiagohm]

Youtube and Twitter features are now available. The other ones might appear in one of the next releases.

[CeJienAJPC]

Thanks for adding the requesting features