Move presentation intro example

Rework images makefile a bit to get it to import and build from resources folder(s).
Currently requires running twice from a clean build due to the way it finds `.dot` files to convert.

docs/resources/PRESENTATION_Intro/counter.v

@@ -0,0 +1,12 @@
+module counter (clk, rst, en, count);
+
+	input clk, rst, en;
+	output reg [1:0] count;
+
+	always @(posedge clk)
+		if (rst)
+			count <= 2'd0;
+		else if (en)
+			count <= count + 2'd1;
+
+endmodule