[rstyle] add tutorial which uses RStyle object
[rstyle] add tutorial which uses RStyle object

Demonstrate c++ API to create and use RStyle.
Later simple text parser should be implemented to work with RStyle.
olifre/root,karies/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,karies/root,olifre/root,olifre/root,root-mirror/root,karies/root,karies/root