Updated define_bc_segmented_s_line_parabola to work properly in all three convergence segments and to use velocity gradient smoothing for the BCs

Merge in r867 from svn: With hydrostatic pressure calculated and output. New failure type DPIII, which reduces dynamic pressure by hydrostatic pressure for specified materials, indicated by material property pore_fluid_pressure.

Merge up to r866 in svn: with new surface types and sedimentation options, for minibasins and combined minibasins with progradation; clean up formatting

Merge up to r856 in svn: With the option to combine progradation and aggradation. This version applies both using the original position of the sedimentation profile, and the total elapsed time. Sedimentation profiles will 'fill in' around one another.

Reverting changes and chosing edge splitting with random addition.