Fix issue #113 (DefaultSerializers.ClassSerializer incorrectly serializing wrapper classes of primitive types). Add a unit test for it.

git-svn-id: http://kryo.googlecode.com/svn/trunk@397 a9660ef0-a895-11de-8ba5-91705c1537ed
Improve the unit test by adding a test for a class which is registered implicitly. In this case a class name is written into the serialized output.

git-svn-id: http://kryo.googlecode.com/svn/trunk@398 a9660ef0-a895-11de-8ba5-91705c1537ed
Significant re-factoring of FieldSerializer which got too complex recently. A lot of logic for handling generic type parameters and unsafe-based serialization is moved into dedicated classes. FieldSerializer is about 350 lines shorter now.

git-svn-id: http://kryo.googlecode.com/svn/trunk@399 a9660ef0-a895-11de-8ba5-91705c1537ed