Code cleanup

Allow sysadmin to specify which env vars to include with the message

Move the getpwuid buffer and size variables into instance data

Make the gearInfo linked list doubly linked and switch to using a
sentinel node.

Add missing free() calls to the hashtable values after they've been
removed from the hashtables.

Hold the mutex longer in doAction so the inotify thread can't delete
data out from under it.

Eliminate memory leaks
Describe updated features