[JPTypeName] avoid string copying. Added assignment operator. Added const-correctness
[JPTypeManager] fixed memory leak for type objects. Made static type maps static members of TypeManager. Added destructor to TypeManager. Changed JPType virtual destructor visability from protected to public (hidden virtual dtors do not make sense) - and this was necessary, because we now delete children of JPType.
Update jp_type.h

fixed authors name
Merge pull request #30 from marscher/minor_cpp_improvements

Minor cpp improvements