add common/sk_mon
add metrics generation script and pass the compiling
change the metrics config hierarchy
move the skull-metrics-gen to the tools folder
support dynamic metrics
add init code both for global and thread metrics
add master metrics and refine part of the metrics initialization code
add metrics for sk core
refine skull_api for logger
remove useless code
move user to top folder
move user to src/user
refactor the per-language implementation
generate metrics before build
add example code for c api
fix bug: logger template cannot load solution message
replace printf with sk_print
replace hard number with macro