[ISSUES-389] Add script to stats test case number

Signed-off-by: Hao yunfeix <yunfeix.hao@intel.com>

command usage: 
For single file:
./stats.py -f ../../webapi/tct-2dtransforms-css3-tests/tests.full.xml
For folder:
./stats.py -r ../../webapi
count item:Suite Name|Total|Total_auto|Total_auto_webdriver|Total_manual|P0|P0_auto|Total_auto_webdriver|P0_manual|P1|P1_auto|P1_auto_webdriver|P1_manual|P2|P2_auto|P2_auto_webdriver|P2_manual|P3|P3_auto    |P3_auto_webdriver|P3_manual|Integrated Upstream TCs|Upstream Resource
Todo:
"tct-fonts-css3-tests","tct-widget02-w3c-tests","tct-manual-w3c-tests","tct-batterystatus-w3c-tests","tct-testconfig","tct-canvas-html5-tests","xwalk-system-tests"
tests.full.xml in these suite cannot use this script, I'll do a search on them and fix this script.