+ random number generator for floats and slices - with tests

I also took the liberty to unify the API between ECMAScript and C.

tests/run/tmath.nim

@@ -0,0 +1,50 @@
+import math
+import unittest
+import sets
+
+suite "random int":
+  test "there might be some randomness":
+    var set = initSet[int](128)
+    for i in 1..10:
+      for j in 1..10:
+        randomize()
+        incl(set, random(high(int)))
+    check len(set) == 100
+  test "single number bounds work":
+    randomize()
+    var rand: int
+    for i in 1..1000:
+      rand = random(1000)
+      check rand < 1000
+      check rand > -1
+  test "slice bounds work":
+    randomize()
+    var rand: int
+    for i in 1..1000:
+      rand = random(100..1000)
+      check rand < 1000
+      check rand >= 100
+
+suite "random float":
+  # Enable this once #197 has been resolved
+  # test "there might be some randomness":
+  #   var set = initSet[float](128)
+  #   for i in 1..10:
+  #     for j in 1..10:
+  #       randomize()
+  #       incl(set, random(1.0))
+  #   check len(set) == 100
+  test "single number bounds work":
+    randomize()
+    var rand: float
+    for i in 1..1000:
+      rand = random(1000.0)
+      check rand < 1000.0
+      check rand > -1.0
+  test "slice bounds work":
+    randomize()
+    var rand: float
+    for i in 1..1000:
+      rand = random(100.0..1000.0)
+      check rand < 1000.0
+      check rand >= 100.0