update readme with install instructions
update readme with install instructions

haiyangd/xmltodict,lucius-feng/xmltodict,ralphbean/xmltodict,sporgj/xmltodict,ahlusar1989/xmltodict,martinblech/xmltodict,butson/xmltodict,CyberTailor/iBlock,bzamecnik/xmltodict,pombredanne/xmltodict,solvebio/xmltodict,pombredanne/xmltodict,martinblech/xmltodict,CyberTailor/iBlock