* added sockaddr_clear() function to zero network addresses before use.
* used this function in p3connmgr.
* added htonll() and ntohll() functions to rsnet.h with compile-time ENDIAN checking
* use htonll() and ntohll() in serialiser.
* added net_test.cc to check network/endian/inet_addr issues.
git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@328 b45a01b8-16f6-495d-af2f-9b41ad6348cc
