Tracker performance test suite

Requirement Analysis
====================
    * Ability to clean up environment
    * Ability to change WatchDir by give parameter
    * Ability to dump interesting values start trackerd until it finish indexing, these values including:
        - StartTime : UTC Time when the tool is called.
        - EndTime   : UTC Time when the tool is finished.
        - InitTime  : trackerd init time, including setting up .db files, tracker.cfg.
        - IndexTime : Trackerd total indexing time for give WatchDir.
        - SourceDirSize: The whole size of WatchDirSize
        - Values for each file types: it is like an summary, it is valuable for storage sensitive system like Sunray     
             FileType: The file types among the WatchDir for give file types
             DocNum:   The documents number among the WatchDir for give file type
             TotalDocSize: The documents total size among the WatchDir for give file type
    * Ability to dump interesting values during trackerd is running
        - Time      : UTC Time when the tool is called.
        - CPU       : The percentage of recent CPU time by trackerd
        - Memory    : The memory size allocated to trackerd
    * Ability to dump testing results into a file (to let other tools analyse it)
                
Preliminary Design
====================
We have implement test suites including:
    * tracker-get-index-time : A tool can get D-Bus message called IndexFinished, get the index time out and print out, written by C.
    * tracker-cleanup  : A tool can cleanup tracker environment, like $HOME/.local/share/tracker, $HOME/.cache/tracker, $HOME/.config/tracker/tracker.cfg, written by shell or python.
    * tracker-test-init  : A tool can get values when start trackerd until it finish indexing, written by shell or python.
    * tracker-test-monitor  : A tool can monitor tracker during running time, record interesting values, written by shell or python.
                
Concept prototype
====================
    * tracker-get-index-time

    * tracker-cleanup
#!/bin/sh
pkill -9 tracker-applet
pkill -9 tracker-preferences
pkill trackerd
rm -rf $HOME/.local/share/tracker
rm -rf $HOME/.cache/tracker
rm -rf $HOME/.config/tracker/tracker.cfg

    * tracker-test-init
#!/bin/sh
/usr/bin/trackerd -R &
index_time=`./get-index-time`
echo $index_time >> index_time.log

    * tracker-test-monitor