Add encoding support

[dagolden]

1. now possible to pick an encoding via the "use" statement

   use M:L:R -readers => { encoding => ... }

2. default is "encoding(UTF-8)"

3. (read|write)_file now take options hashref and allow 'encoding'

[dagolden]

Addresses #1

[rjbs]

I have reviewed this and I think it is all good. I will try to merge it at once with a few other changes.

[dagolden]

As I reflect on @dolmen's original concern, perhaps the "encoding" option should be renamed "binmode" for clarity. (FWIW, that's the name I used for Path::Tiny.) Then people will get that ":raw" or ":utf8" or ":utf8_strict" or ":encoding(UTF-8)" are all legitimate.

[rjbs]

I prefer binmode also. I was going to suggest it once I saw your patch, but decided it wasn't worth worrying about. I'm glad somebody else mentioned it, because I like it better, too.

[dolmen]

👍 for binmode: this makes explicit that an I/O layer is expected instead of a bare encoding name.

[rjbs]

This is now in a trial release.

[haarg]

Doesn't this break 5.6 compatibility? The metadata should be updated to reflect that. Also, IO::String could be dumped in favor using PerlIO.

[rjbs]

I have added a prereq for 5.8.1

The IO::String, I'll look at doing a bit later, thanks.