Adds index for better logging

Author: moo24

kotlin/src/com/here/flexiblepolyline/FlexiblePolyline.kt

@@ -115,7 +115,7 @@ object FlexiblePolyline {
             require(!(precision < 0 || precision > 15)) { "precision out of range" }
             require(!(thirdDimPrecision < 0 || thirdDimPrecision > 15)) { "thirdDimPrecision out of range" }
             require(!(thirdDimensionValue < 0 || thirdDimensionValue > 7)) { "thirdDimensionValue out of range" }
-            val res = (thirdDimPrecision shl 7 or (thirdDimensionValue shl 4) or precision).toLong()
+            val res = ((thirdDimPrecision shl 7) or (thirdDimensionValue shl 4) or precision).toLong()
             Converter.encodeUnsignedVarInt(VERSION, result)
             Converter.encodeUnsignedVarInt(res, result)
         }
@@ -248,10 +248,10 @@ object FlexiblePolyline {
                 var shift: Short = 0
                 var result: Long = 0
 
-                encoded.forEach {
-                    val value = decodeChar(it).toLong()
+                encoded.withIndex().forEach {
+                    val value = decodeChar(it.value).toLong()
                     if (value < 0) {
-                        throw IllegalArgumentException("Unexpected value found :: '$it")
+                        throw IllegalArgumentException("Unexpected value found :: '${it.value}' at ${it.index}")
                     }
                     result = result or ((value and 0x1FL) shl shift.toInt())
                     if ((value and 0x20L) == 0L) {