- use lib FindBin::Bin in tests, preparing for perl 5.26 where '.'
  gets removed from @INC. Fixes issue#54 TINITA++
- Use the latest libyaml sources.
- Lazy load B::Deparse for faster startup time.
  Applied PR/53 by @perlpunk++
  (submitted by @carnil++ from a Debian issue as GitHub issue#52)