Fossil

**  - PIKCHR_PROCESS_DIV_SOURCE: adds the 'source' CSS class to the
**    outer DIV, which is a hint to the client-side renderer (see
**    fossil.pikchr.js) that the pikchr should initially be rendered
**    in source code form mode (the default is to hide the source and
**    show the SVG).
**
**  - PIKCHR_PROCESS_DIV_SOURCE_INLINE: adds the 'source-inline' CSS
**    class to the outer wrapper. If PIKCHR_PROCESS_DIV_SOURCE is
**    specified, this modifier indicates that the source code view
**    should be rendered "inline" (same position as the graphic), else
**    it is to be left-aligned.
**
** - PIKCHR_PROCESS_NONCE: if set, the resulting SVG/DIV are wrapped
** in "safe nonce" comments, which are a fossil-internal mechanism
** which prevents the wiki/markdown processors from re-processing this
** output. This is necessary when calling this routine in the context

        const char *zNonce = (PIKCHR_PROCESS_NONCE & pikFlags)
          ? safe_html_nonce(1) : 0;
        if(zNonce){
          blob_appendf(pOut, "%s\n", zNonce);
        }
        if(PIKCHR_PROCESS_DIV & pikFlags){
          if(PIKCHR_PROCESS_DIV_CENTER & pikFlags){
            /*blob_append(&css, "display:block;margin:auto;", -1);*/
            zWrapperClass = " center";
          }else if(PIKCHR_PROCESS_DIV_INDENT & pikFlags){
            zWrapperClass = " indent";
          }else if(PIKCHR_PROCESS_DIV_FLOAT_LEFT & pikFlags){
            zWrapperClass = " float-left";
          }else if(PIKCHR_PROCESS_DIV_FLOAT_RIGHT & pikFlags){
            zWrapperClass = " float-right";