Structure.js component

I created a React Structure.js component that supports viewing atomistic structures. It is now initially integrated into the ArchiveBrowser where it will show the structure for any section_system below the title.

You can check it in action at the development cluster, e.g. here In the context of the ArchiveBrowser the viewer tries to intelligently load new data:

• There is only one shared instance of StructureViewer object from the materia-library.
• If a new structure is loaded from the same archive, only the positions are updated. This is much faster than reloading the entire structure and should be a valid assumption since the number of atoms or their species should not change within an archive.
• If more than 300 atoms (this is configurable) are present, the visualization is disabled and a message is displayed.