Apply flags for default values

[Zetazzz]

added setDefaultEnumTo0(default: false):

true: enum empty value would be 0
false: -1(value for enum unrecognized)

added setDefaultOtherTypesToUndefined(default: false):

true: Timestamp,Duration,Any,Coin empty would be undefined.
false: using fromPartial to get an empty obj

[pyramation]

if you can build the types properly, LGTM!