update: refactor README.md and test code
refactor: Cmp2 -> Cmp3
refactor: beautify the multi-row string output
update: add caller funcname
update: add t.Submatch
update: TestLevel0 change
update: remove temp code
update: lenXXX if para is int, output don't print "len="
update: remove StrEqual
update: newStrResultPara1 -> newResult1StrPara
update: remove StrXXX, only keep Contains
udpate: finished Submatch
update: refactor file name
update: StructEqual -> FieldEqual
update: study.md+frament.md -> memo.md