Spo unified

This adds a new output plugin for writing to a single unified formatted log. This allows for multiple snort instances to run, each with their own by2 instance using this output plugin, and another single by2 instance for the final output. 

Useful in situations where multiple instances of snort are running but you only want to maintain a single mysql connection open.

Bad things:
I do not have access to a non-unix'y operating system and I am sure that the file locking mechanisms are different on windows, so this will probably fail on win32. Could optionally ifdef it out for now.