reorganized the sockets example programs a little.

--HG--
rename : examples/sockstreambuf_ex.cpp => examples/server_iostream_ex.cpp
rename : examples/sockets_ex_2.cpp => examples/sockstreambuf_ex.cpp

implementation component.  So no real functional code changes in this commit.

--HG--
rename : dlib/sockstreambuf/sockstreambuf_kernel_2.cpp => dlib/sockstreambuf/sockstreambuf.cpp
rename : dlib/sockstreambuf/sockstreambuf_kernel_2.h => dlib/sockstreambuf/sockstreambuf.h
rename : dlib/sockstreambuf/sockstreambuf_kernel_abstract.h => dlib/sockstreambuf/sockstreambuf_abstract.h
rename : dlib/sockstreambuf/sockstreambuf_kernel_1.cpp => dlib/sockstreambuf/sockstreambuf_unbuffered.cpp
rename : dlib/sockstreambuf/sockstreambuf_kernel_1.h => dlib/sockstreambuf/sockstreambuf_unbuffered.h

the output slightly nicer looking.

in the last change.

user perspective anyway).

Also added find_trees_not_rooted_with_tag().