updated TODO.
added a lib. in Makefile to build on Ubuntu 13.04.

Before applying this patch, we got the following error.

/usr/bin/ld: zabbix-api-response-collector.o: undefined reference to symbol 'g_object_unref'
/usr/bin/ld: note: 'g_object_unref' is defined in DSO /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 so try adding it to the linker command line
removed __GLIBCXX_USE_NOEXCEPT qualifier on the platform that doesn't supported it such as CentOS 6.3.