Add text support

[raykov]

No description provided.

[srwiley]

Raykov, I will definitely look into this. Is there are reason you deleted the pull request? Text features can be basic, rather than doing the full SVG implementation, which is quite elaborate. That is why we call it oksvg.
Also it would be good to put these new features into a separate file so that the core files do not become too large and generic. Finally, adding testing makes it much easier for me to accept a pull request. This can be done by adding a few test files into the example testing folder.
Thank you for your efforts.