Release of FDS 6.7.6

[Kevin]

 A new maintenance release of FDS and Smokeview is available for download at 

https://pages.nist.gov/fds-smv/downloads.html

Release notes can be found at 

https://github.com/firemodels/fds/wiki/FDS-Release-Notes

For those of you who have been having difficulties with tunnel fire scenarios, you might want to search the new User's Guide for the parameter TUNNEL_PRECONDITIONER. This parameter has the effect of stabilizing the pressure and velocity fields in long tunnels with fires and solid interior walls.

[Anthony Marcozzi]

Thank you for all of your hard work!