Cleanup/improve PList usage and Event API

Majority of PLists are now created as automatic/stack objects,
rather than on heap and initialized either with the known-capacity
reserved upfront or directly from an initializer_list (so there's no
wasted slack in the memory that gets allocated for lists containing
a fixed/known number of elements).

Added versions of the ConnectionEvent/QueueEvent methods that take
a val_list by value.

Added a move ctor/assign-operator to Plists to allow passing them
around without having to copy the underlying array of pointers.

src/file_analysis/File.h

@@ -172,6 +172,12 @@ public:
 	 */
 	void FileEvent(EventHandlerPtr h, val_list* vl);
 
+	/**
+	 * Raises an event related to the file's life-cycle.
+	 * @param h pointer to an event handler.
+	 * @param vl list of argument values to pass to event call.
+	 */
+	void FileEvent(EventHandlerPtr h, val_list vl);
 
 	/**
 	 * Sets the MIME type for a file to a specific value.