Add tasks for all the new languages

Task/Reverse-a-string/Phix/reverse-a-string-1.phix

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+?reverse("asdf")

Task/Reverse-a-string/Phix/reverse-a-string-2.phix

@@ -0,0 +1,19 @@
+function unicode_reverse(string utf8)
+sequence utf32 = utf8_to_utf32(utf8)
+integer ch
+    -- the assumption is made that <char><comb1><comb2>
+    -- and <char><comb2><comb1> etc would work the same.
+    for i=1 to length(utf32) do
+        ch = utf32[i]
+        if (ch>=0x300 and ch<=0x36f)
+        or (ch>=0x1dc0 and ch<=0x1dff)
+        or (ch>=0x20d0 and ch<=0x20ff)
+        or (ch>=0xfe20 and ch<=0xfe2f) then
+            utf32[i] = utf32[i-1]
+            utf32[i-1] = ch
+        end if
+    end for
+    utf32 = reverse(utf32)
+    utf8 = utf32_to_utf8(utf32)
+    return utf8
+end function