Add repeater and delay to timestamp parsing

[calmofthestorm]

Please review after #30 , as this is rebased on top of it.

Rework timestamp parsing in a few ways:

• Add repeaters and delays as their own types.
• Fix range types to support repeaters and delays at both start and end.
• Parse repeaters and delays.
• Make dayname optional.
• Add Parse trait to allow users to parse individual elements from a &str.
• Implement TryFrom<&str> for Parse.
• Implement Parse/TryFrom<&str> for all timestamp parts.
• Substantially increase timestamp test coverage for new and existing cases.

[calmofthestorm]

I believe I addressed the requested changes.

[jobnbackpack]

hey there, just wondering if this PR will finish any time soon ^^

[calmofthestorm]

@PoiScript Do you remember what the blocker here was? It's been awhile.

@jobnbackpack FWIW, these days I use starsector to parse the document, then use orgize to parse specific sections as needed. It supports parsing planning timestamps including repeats.

[jobnbackpack]

Okay, I will look into it! Right now I just patched your PR branch with Cargo. That works for now I guess ^^

[PoiScript]

@jobnbackpack @calmofthestorm sorry for the late reply, repeater and delay in timestmap are supported in v0.10.0-alpha.4.