[TASK] Add a constant for the maximum number representable as a Ripple value.

src/js/ripple/amount.js

@@ -33,6 +33,10 @@ var consts = exports.consts = {
 
   cMinOffset:        -96,
   cMaxOffset:        80,
+
+  // Maximum possible amount for non-XRP currencies using the maximum mantissa
+  // with maximum exponent. Corresponds to hex 0xEC6386F26FC0FFFF.
+  max_value:         '9999999999999999e80'
 };
 
 

src/js/ripple/serializedtypes.js

@@ -345,7 +345,7 @@ var STAmount = exports.Amount = new SerializedType({
 
         // Next eight bits: offset/exponent
         hi |= ((97 + amount._offset) & 0xff) << 22;
-        // Remaining 52 bits: mantissa
+        // Remaining 54 bits: mantissa
         hi |= amount._value.shiftRight(32).intValue() & 0x3fffff;
         lo = amount._value.intValue() & 0xffffffff;
       }