hibari >> GH18 - Add DTrace tracepoints for Erlang/OTP R15 or later
- Rename function gmt_elog_policy:enabled/6 to dtrace/6, and apply
  dyntrace:p/5 in there
- Add the global switch 'dtrace_support' to sys.config to enable/
  disable this feature
- Add gmt_elog_policy:dtrace_support/0, which returns 'dyntrace' |
  'disabled' | 'unsupported'
- Add a warning log for when 'dtrace_support' config is set to true
  but dynamic trace is not available in Erlang VM