Add Haskell solutions for Problems 1, 2, 3

Haskell/p001.hs

@@ -0,0 +1,12 @@
+-- If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
+--
+-- Find the sum of all the multiples of 3 or 5 below 1000.
+sumMultiples :: (Integral n) => n
+sumMultiples = sum(filter p [ n | n <- [1..999] ])
+                where p n = n `mod` 3 == 0 || n `mod` 5 == 0
+
+main :: IO ()
+main =  do
+    let result = sumMultiples
+    putStrLn $ "Project Euler, Problem 1\n"
+        ++ "Answer: " ++ (show result)