v0.0.15

• Update zoneinfo64 by @Manishearth in #552
• Remove Default impl from TimeZone; use utc() everywhere by @Manishearth in #551
• Add missing header files by @Manishearth in #550
• Add provider APIs to capi by @Manishearth in #544
• Add new unit validation code by @Manishearth in #542
• Add calendar consts for calendar construction by @nekevss in #541
• Remove some unreachables by @Manishearth in #543
• Move timezone tests to testing against multiple providers by @Manishearth in #539
• Move TimeZone over to being Copy with TimeZoneId by @Manishearth in #538
• Split TimeZoneProvider trait by @Manishearth in #537
• Update compiled tzif data provider data by @nekevss in #535
• Add zoneinfo64 support to temporal_provider by @Manishearth in #533
• Update zoneinfo compilation in zoneinfo crate by @nekevss in #532
• Complete some cleanup options module by @nekevss in #531
• Make errors Copy by @Manishearth in #528
• More saturating arithmetic by @Manishearth in #527
• Move TimeZoneProvider to timezone_provider crate by @Manishearth in #526
• Clean up TimeZoneProvider crate by @Manishearth in #525

Full Changelog: v0.0.14...v0.0.15