C++ Binding: changes for version 1.0a

The following changes were made between versions 1.0 and 1.0a of the ZOOM C++ binding:

1. Added CVS comment
2. Added Z3950 namespace around all declarations
3. Added ``public:'' label to Z3950, Z3950_connection, Z3950_resultSet, Z3950_record, Z3950_system_error and Z3950_bib1_error classes
4. Added ``const'' qualifier to all char* parameters
5. Added ``const'' qualifier to most char* return types, except those of Z3950::errmsg(), Z3950::addinfo(), Z3950_record::field(), Z3950_record::render() and Z3950_record::rawdata()
6. Added ``const'' qualifier to all void* parameters and return types
7. Added space before parameter-list parentheses
8. Used separate overloaded option() methods for getting/setting
9. Added the Z3950_asimple_search class (subclass of Z3950_search)
10. Added ``const'' modifier suffix to some methods - but, I think, not all that could have it added?
11. Renamed Z3950_record()::rawdata()'s sizep parameter to psize
12. Added ``int errcode'' to Z3950_system_error interface
13. Added ``int i'' to Z3950_system_error implementation
14. Added ``int i, char *pc'' to Z3950_bib1_error implementation