- renamed "description()" member to "errorString()", 
   - renamed "where" attribute to "description", 
   - changed "what()" ouptut.

Utils/Logger: Add some internal implementation documentation concerning SENF_LOG_CLASS_AREA()

Utils/Logger: Renoame all 'SENF_LOG_DEF_*' macros to 'SENF_LOG_DEFINE_*'
Utils/Logger: Add documentation on default compile-time limit

Socket/Protocols/INet: Fix INet6SocketAddress base classes

Packets: change *_RO field helper macros to add a private r/w accessor
senfscons: Introduce TEST_EXTRA_LIBS variable and move BOOSTFSLIB there
Socket/Protocols/INet: Make INet[46]MulticastSocketProtocol inherit MulticastSocketprotocol
Change SENF_NO_DEBUG to SENF_DEBUG

- some documentation updates, once again