fixed demux td 2 unit test and added note to prims

dataflow_neuro/primitives.act

@@ -393,6 +393,8 @@ namespace tmpl {
         // WARNING WARNING WARNING
         // With a False CONDITION_SIGN, this is wrong.
         // the c.t/f just need to be swapped, not inverted!!!
+        // @TODO self explanatory
+        // also note this is not used in the final texel chip
         defproc demux_td (avMx1of2<N> in; avMx1of2<N> out; a1of1 token; bool? reset_B; avMx1of2<1> cond; power supply) {
             //control
             bool _en, _reset_BX,_reset_BXX[N], _out_v, _in_c_v_, _reset_BXt;