Add tasks for all the new languages

Task/Gray-code/Nim/gray-code-1.nim

@@ -0,0 +1,9 @@
+proc grayEncode(n): auto =
+  n xor (n shr 1)
+
+proc grayDecode(n): auto =
+  result = n
+  var t = n
+  while t > 0:
+    t = t shr 1
+    result = result xor t

Task/Gray-code/Nim/gray-code-2.nim

@@ -0,0 +1,4 @@
+import strutils
+
+for i in 0 .. 32:
+  echo i, " => ", toBin(grayEncode(i), 6), " => ", grayDecode(grayEncode(i))

Task/Gray-code/Phix/gray-code.phix

@@ -0,0 +1,21 @@
+function gray_encode(integer n)
+    return xor_bits(n,floor(n/2))
+end function
+
+function gray_decode(integer n)
+integer r = 0
+    while n>0 do
+        r = xor_bits(r,n)
+        n = floor(n/2)
+    end while
+    return r
+end function
+
+integer e,d
+puts(1," N  Binary Gray   Decoded\n"&
+       "==  =====  =====  =======\n")
+for i=0 to 31 do
+    e = gray_encode(i)
+    d = gray_decode(e)
+    printf(1,"%2d  %05b  %05b  %2d\n",{i,i,e,d})
+end for

Task/Gray-code/Sidef/gray-code.sidef

@@ -0,0 +1,14 @@
+func bin2gray(n) {
+    n ^ (n >> 1);
+}
+
+func gray2bin(num) {
+    var bin = num;
+    while (num >>= 1) { bin ^= num };
+    return bin;
+}
+
+0..31 -> each { |i|
+    var gr = bin2gray(i);
+    printf("%d\t%b\t%b\t%b\n", i, i, gr, gray2bin(gr));
+}