Currently, when calling the API, the precision ofa time value has to be specified using an obscure number, e.g. 8 for a decade or 0 for a gigayear. We should accept obvious string values for these, and map them to the internal numeric representation during deserialization of the JSON structure supplied to the API call. We'll want at least the following to work:

"gigayear" => 0,
"megayear" => 3,
"kiloyear => 6,
"century" => 7,
"decade" => 8,
"year" => 9,
"month" => 10,
"day" => 11,
"hour" => 12,
"minute" => 13,
"second" => 14,