add missing -always_recommend flags

now also recommending prereqs:
    MooseX::Storage::Format::JSONpm
    YAML
    YAML::Syck 0.01
make use of -default = 1 in optional feature specifications
Dist::Zilla 4.300038 has a workaround for the yaml encoding issue (see rjbs/Dist-Zilla#200)
MooseX-Storage-0.42

  - all features are now configured as x_default => 1 in metadata (not yet
    supported by any cpan clients), signalling to automatically add to prereqs
    when installing non-interactively
  - re-release with properly encoded META.yml