util: Check if m_socket is a null pointer before closing it in the destructor.

Credit for fix goes to JoeBell, thanks!
StateServer: Fix incorrect type in handle_parent_change.

Credit for fix goes to JoeBell, thanks!
includes: Add #include <stdint.h> to top of messages.h, to ensure types are defined.

Credit for fix goes to JoeBell, thanks!
EventLogger: Initialize m_file pointer to 0 in constructor.

Credit for fix goes to JoeBell, thanks!
Merge pull request #82 from OpenOTP/joebell-fixes

Fixes from Freenode user JoeBell