Integrate with RNAFramework

[AntonPetrov]

It would be useful to establish an integration with RNAFramework so that R2DT can be used to display the secondary structure and reactivities produced by RNAFramework.

R2DT should read RNAFramework's XML files and generate structure using the template-free algorithm and display reactivities as data layers. See RNAFramework docs for more info.

@dincarnato Danny, please feel free to point to an example XML file (no rush on this, just making sure this does not fall through the cracks).