plot_SS_panel: Plot silver-standard (SS) panel
In zhenkewu/nplcm: Nested Partially-Latent Class Models (nplcm)

Now only works for singleton etiologies. Current the prior shape can only be represented by intervals.

1 2	plot_SS_panel(MSS, model_options, clean_options, res_nplcm, bugs.dat, top_SS = 0.3, cexval = 1, srtval = 0)

`MSS`	Matrix of silver-standard measurements. Rows for subjects (cases at the top, controls at the bottom), columns for pathogen-specimen combination. `MSS` has fewer columns than MBS and those pathogens with both BrS and SS measurements should be arranged in the first several columns. This should have been done by `clean_perch_data`.
`model_options`	See `nplcm`
`clean_options`	See `clean_perch_data`
`res_nplcm`	See `nplcm_read_folder`
`bugs.dat`	Data input for the model fitting.
`top_SS`	Default is `0.3`. Numerical value to specify the rightmost limit on the horizontal axis for the SS panel.
`cexval`	Default is 1 - size of text of the BrS percentages.
`srtval`	Default is 0 - the direction of the text for the BrS percentages.