Comparing Datetime libs in Rust

This Benchmark Suite compares:

• chrono
• iso8601 (pure parsing, no validation, see blog post)
• datetime (uses iso8601 0.1)
• dtparse

Benches

test chrono02_bench::parse_iso8601       ... bench:         229 ns/iter (+/- 31)
test chrono03_bench::parse_iso8601       ... bench:         419 ns/iter (+/- 39)
test chrono04_bench::parse_iso8601       ... bench:         426 ns/iter (+/- 37)
test datetime_bench::parse_iso8601       ... bench:         166 ns/iter (+/- 37)
test dtparse_bench::parse_iso8601        ... bench:       7,108 ns/iter (+/- 1,597)
test iso8601_v01_bench::parse_iso8601    ... bench:         130 ns/iter (+/- 22)
test iso8601_v03_bench::parse_iso8601    ... bench:         145 ns/iter (+/- 22)
test iso8601_v04_bench::parse_iso8601    ... bench:         119 ns/iter (+/- 19)
test iso8601_master_bench::parse_iso8601 ... bench:         142 ns/iter (+/- 31) // oops
test regex_bench::parse_iso8601          ... bench:         616 ns/iter (+/- 147)