remove boost libraries from repository

these libraries should have been already compiled on the machine rather than coming already compiled from the repository
deactivate VS post-build event
add Windows XP support
rewrite callback handler code
major code rewrite

this introduces these changes:
- replaced old thread implementation with boost::thread
- replaced old sockets implementation with boost::asio
- restructured native representation in code
- split callback code logically
- code cleanup
- increased reliability by forcing a delay after each socket write
- CTeamspeak class is now a singleton
- removed all documentation from the include file
- added new native "TSC_ChangeNickname" to change the nickname of the logged-in server-query