#12 Implement core admin, main method Action for making call admin endpoint admin/cores
#12 the format must also be in json
#12 remove 'to' to make it less confused
#12 always forget that go has different kind switch statement. Make action case insensitive then we added it
#12 step up version
Merge pull request #20 from vanng822/12_core_admmin

Implement core admin, see #12