v0.9.6

• Change AFCPluginPlugin to AFPluginManager, make it easier to use.
• Restructure the file directories, make plugin easier and standalone to be used by other projects.
• Fix the crash bug of the parsing network message.
• Redo the macros.
• Add StringUtils and Slice class.
• Update spdlog to v1.3.1.
• Use functor as parameters(old version is functor ptr).
• Add chain expression in the network plugin.
• Change the dependencies to git submodules.
• Format by clang-format.
• Fix some memory leak.