Add selection sort

SelectionSort.nim

@@ -0,0 +1,16 @@
+proc selectionSort(list:seq[int]):seq[int] =
+    result = list
+
+    proc indexOfMin(list:seq[int], startIndex:int): int =
+        result = startIndex
+        for i in startIndex .. list.high:
+            if list[i] < list[result]:
+                result = i
+
+    for i in result.low .. result.high:
+        swap(result[i], result[result.indexOfMin(i)])
+
+when isMainModule:
+    let
+        seq1 = @[1, 3, 2, 56, 2, 1, 32, 45, 23, 41, 6, 47, 212, 32, 6, 98, 54, 457, 37, 4]
+    echo seq1.selectionSort