update doc
update doc

lisong521/easyloggingpp,spthaolt/easyloggingpp,lisong521/easyloggingpp,dreal-deps/easyloggingpp,blankme/easyloggingpp,spthaolt/easyloggingpp,utiasASRL/easyloggingpp,blankme/easyloggingpp,hellowshinobu/easyloggingpp,spqr33/easyloggingpp,chenmusun/easyloggingpp,arvidsson/easyloggingpp,spqr33/easyloggingpp,dreal-deps/easyloggingpp,chenmusun/easyloggingpp,simonhang/easyloggingpp,chenmusun/easyloggingpp,utiasASRL/easyloggingpp,utiasASRL/easyloggingpp,simonhang/easyloggingpp,hellowshinobu/easyloggingpp,blankme/easyloggingpp,lisong521/easyloggingpp,spthaolt/easyloggingpp,spqr33/easyloggingpp,dreal-deps/easyloggingpp,hellowshinobu/easyloggingpp,arvidsson/easyloggingpp,simonhang/easyloggingpp,arvidsson/easyloggingpp