Solved some problems, improved code quality and added new features.

* Added some Solr data types to SolrType enumerator and adjusted code to
treat this new data types.
* Added suport to List<T> data to the ToArray() XElement extension and
ajusted code to return List<T> properties as espected.
* Renamed some parameters and local variables to a more meaningful name.
* Solved problems with date conversion.
* Enhanded Complex sample to use most of data types including a array
sample.
* Cleaned some useless code.