Plan for TOML v0.4 compliance

[pygy]

The spec has been vastly improved and extended since TOML v0.2.0 implemented by this library:

v0.4.0

• Add Inline Table syntax.
• Allow underscores in numbers.
• Remove forward slash as an escapable character.
• Unicode escapes must be scalar values.
• Newline is now defined as LF or CRLF.

v0.3.0

• Add scientific notation for floats.
• Allow optional + prefix on integers.
• Switch to RFC 3339 for datetimes (allowing offsets and fractional seconds).
• Add multiline and literal strings.
• Clarify what characters valid keys can contain.

[PallHaraldsson]

FYI 0.5.0 is out: "As of version 0.5.0, TOML should be considered extremely stable. The goal is for version 1.0.0 to be backwards compatible (as much as humanly possible) with version 0.5.0."

[PallHaraldsson]

I see now 0.4.0 is supported by JuliaAttic/TOML_old.jl#11 and I pointed them at 0.5.0.

Here README should maybe say something? I assume this project is outdated and the other one better in every way?!

[PallHaraldsson]

I'm no longer sure, if outdated here, as I see this package registered, and didn't locate the other package at:
https://github.com/JuliaRegistries/General/blob/master/T/TOML/Package.toml

Is it possible to switch there? I've not looked up what to do for name conflicts, but at would also only want to switch if for sure the same API... Can this package reuse the other one if not?