add support to error statistics ui
correct wrong log level in cosbench-mock and cosbench-swift
ui support
Merge branch '0.4.0.1' of https://github.com/xiaoerlyl/cosbench into 0.4.0.1
add support on driver side
remove the improper implementation on controller side
refine driver state on controller web interface
Merge pull request #205 from xiaoerlyl/0.4.0.1

add error statistics on driver web, and also fix the inconsistent driver state issue (#203)