boilerplate for plasmas

funcs/tests.h

@@ -3,6 +3,8 @@
 	see also: t.c & tests.c
  */
 
+int essai_plasma(char *infile, char *outfile, int ikoef, float fkoef);
+
 int essai_displacement(char *infile, char *outfile);
 int essai_qsort_rgb(char *infile, char *outfile);
 int essai_equalize(char *infile);