Add tasks for all the new languages

Task/Roman-numerals-Decode/Ring/roman-numerals-decode.ring

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+symbols = "MDCLXVI"
+weights = [1000,500,100,50,10,5,1]
+
+see "MCMXCIX = " + romanDec("MCMXCIX") + nl
+see "MDCLXVI =" + romanDec("MDCLXVI") + nl
+see "XXV = " + romanDec("XXV") + nl
+see "CMLIV = " + romanDec("CMLIV") + nl
+see "MMXI = " + romanDec("MMXI") + nl
+
+func romanDec roman
+     n = 0
+     lastval = 0
+     arabic = 0
+     for i = len(roman) to 1 step -1
+         n = substr(symbols,roman[i])
+         if n > 0 n = weights[n] ok
+         if n < lastval arabic = arabic - n
+         else arabic = arabic + n ok
+         lastval = n
+     next
+     return arabic