add search engine feature
add history feature
remove duplicate and print newline
separate SETPROP and SETPROPCACHE
allow default engine
vi-liked keybind
remove default search engine, it cause problem with history; now use space to indicate we run search engine or not
use space to indicate it's seachengine request
default search engine sinal with beginning space
Merge remote-tracking branches 'origin/history' and 'origin/searchengines'