Added HandlerSocket plugin

- Fixed compiler errors
- Modified Makefiles to be part of plugin directory
- Some minor changes in database.cpp to use the new MariaDB handler interface

plugin/handler_socket/perl-Net-HandlerSocket/README

@@ -0,0 +1,30 @@
+HandlerSocket version 0.01
+==========================
+
+The README is used to introduce the module and provide instructions on
+how to install the module, any machine dependencies it may have (for
+example C compilers and installed libraries) and any other information
+that should be provided before the module is installed.
+
+A README file is required for CPAN modules since CPAN extracts the
+README file from a module distribution so that people browsing the
+archive can use it get an idea of the modules uses. It is usually a
+good idea to provide version information here so that people can
+decide whether fixes for the module are worth downloading.
+
+INSTALLATION
+
+To install this module type the following:
+
+   perl Makefile.PL
+   make
+   make test
+   make install
+
+DEPENDENCIES
+
+COPYRIGHT AND LICENCE
+
+  Copyright (C) 2010 DeNA Co.,Ltd.. All rights reserved.
+  See COPYRIGHT.txt for details.
+