mailproc improvements:

If a "Command" key value is included in .ini file, will be used in place of
mail processor's name (section name in square brackets).
If an "Eval" key value is included in .ini file (for non-native mail procs),
the key value will be JS-evaluated instead of executing an external script.
Fix: If a message is received for multiple local recipients and any of the
names match a mailproc's 'to' list, that mail processor will be executed.
These improvements and fixes allow a mailproc.ini entry like the following to
work:
[From Hosted Address]
	From = *@synchro.net,*@swindellfamily.com,*@weedpuller.com
	AccessRequirements=not user 1
	Eval = log("Removing mail from " + reverse_path); file_remove(message_text_filename)