Adding euler: cs and erlang, and a Makefile for cleaning and basic building

Makefile

@@ -0,0 +1,6 @@
+
+default:
+	mcs *.cs
+
+clean:
+	rm -r -f *.exe *.beam

e1.cs

@@ -0,0 +1,13 @@
+using System;
+
+public class E1
+{
+	public static void Main() {
+		int sum = 0;
+		for(int i = 2; i < 1000; i++) {
+			if (i % 3 == 0 || i % 5 == 0) 
+				sum += i;
+		}
+		System.Console.WriteLine(sum);
+	}
+}

e1.erl

@@ -1,4 +1,13 @@
 -module(e1).
--export([e1/1]).
+-export([e1/0]).
 
-e1(
+add_list([], Acc) -> Acc;
+add_list([X| Tail], Acc) -> add_list(Tail, Acc+X).
+
+find_3_5_divisibles(Start, Max) -> find_3_5_divisibles(Start, Max, []).
+
+find_3_5_divisibles(Max, Max, Acc) -> Acc;
+find_3_5_divisibles(Start, Max, Acc) when Start rem 3 == 0; Start rem 5 == 0 -> find_3_5_divisibles(Start+1, Max, [Start |Acc]);
+find_3_5_divisibles(Start, Max, Acc) -> find_3_5_divisibles(Start+1, Max, Acc).
+
+e1() -> add_list(find_3_5_divisibles(2, 1000), 0).