[Tracker] work items for 0.6.5

[Jamie McCracken <jamiemcc blueyonder co uk>]

There are a few things that need doing before for 0.6.5 so if any of you
has time to spare (i have little) so feel free to volunteer:

1) add an optional auto-pause feature to tracker-applet which pauses
trackerd for a few secs whenever a keyboard or mouse event is detected
(use gdk to listen to X event queue for this just like screensavers
do). 

this feature would prevent trackerd from slowing down the computer
whenever the user is actively using the machine


2) Ignore maildirs - currently these are treated as text files but its
best to ignore them for now as they can overload the files db with
millions of mail msgs

maildirs always has a directory with 3 subdirs - "cur",  "new" and "tmp"
- if we detect a directory with just those subdirs then we should ignore
them and not process anything in them (in the future if we have good
email detection we can process them as emails but its too tricky to do
so atm)


3) Constantly changing files - we should ignore these especially
bittorrent ones. Perhaps keep a small size-limited stack of recently
indexed files and if one of those files has been changed more than 10
times in a few minutes we should ignore them until trackerd next
restarts

jamie