add slides of DataAnalysis
add version to 0.3.1
add more dependencies
update DA
Merge branch 'master' into feat/add_DA

Conflicts:
	DESCRIPTION
add DA_file API for estate_linux.rds
add libxml2-dev for ubuntu
Merge remote-tracking branch 'twruser/master'
update helper functions for slides
Merge remote-tracking branch 'origin/master' into feat/add_DA
add the version of George
Merge pull request #16 from wush978/feat/add_DA

Feat/add da