Throw error message for arrays

[sockeqwe]

Originally reported in #44

Arrays are not supported because Arrays are inefficient to parse because we have to know the size of the array, which means we have to read the whole xml document and store the values somewhere temporary (i.e. in a list) to know the final size of the array and then we have to copy the values from temporary structure into array.
Therefore, we don't have plans to support arrays.

However, we should throw a compiler error message if people try to use arrays, but this would disallow using a global TypeConverter for arrays, but I think that this is acceptable.