Add note about app frameworks to readme.
Add note about app frameworks to readme.

mpetroff/pannellum,psteph801/psteph801.github.io,psteph801/psteph801.github.io,mpetroff/pannellum,psteph801/psteph801.github.io,mpetroff/pannellum,psteph801/psteph801.github.io,mpetroff/pannellum