When deserializing we currently cutoff at 6. This is correct so far as the spec is concerned (ie. the spec lets you do whatever), but 7 has been observed in practice.
For future proofing, probably just want to support out to one Ticks resolution (100 nanoseconds).
I hate ISO8601.
add 1 extra char to DateTime deserialization for 7 digit (ie. 1 tick …
…resolution) datetime support; fixes #43
get started #42; found a bug in the fix for #43 as well, test fixed
fix #43 for real, switches to using tick resolution for all deseriali…