Add missing include
Search for jpeglib.h

Only search for jpeglib.h. Otherwise CMake will find the return the path for the first found header.
Check if jpeg_src_mem is already implemented using MEM_SRCDST_SUPPORTED

Additionally change the signature of jpeg_src_mem to match the one provided
by libjpeg-turbo.
Fix a gcc warning about missing initializer for members
Disable -Wclobbered for PNG de-/compression methods
Add function templates to serialize/deserialize some of the virvo classes.

Will later be used with Boost.Serialization.
Add initial versions of new networking classes using Boost.ASIO.

These classes are not used yet - just see if everything compiles and links fine.