#9 cbyt default scaling should change

[seismick]

In cbyt, when Variable Density display is selected, and then in Color Options,
for Percentiles, the default is 100%. This yields a weak display. If PNC and PPC are changed to 98.5, a better display results. It is awkward to change the sliders, so the defaults should be 98.5 percent. This is in the source file seis_color_pop.cc.
For wiggle and variable area mode displays, Ct has a default value of 4, which is also yields a weak display. A default of 5 would be better. However, it is easier for users to change this than the PNC and PPC values for variable density. Default Ct is set in source file seis_select.cc.