v2.2 release
v2.2 release

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