simplify rounding to be consistent between expression and absolute

relative time rounding fixes

v1.3.0 - Null and Present support for slices

Support unmarshaling into slices (#4)

support marshaling slice back to json (gocraft#28) (#3)

Co-authored-by: Ben Wheeler <[email protected]>

Merge pull request #1 from uservoice/json-unmarshall

JSON unmarshall

add go mod