Typed tables, check for a way to omit columns if default/null

[sl-at-ibm]

To avoid unecessary tombstones, and also allow partial writes that do not overwrite certain columns, typed tables should have an easy way to do this.

Right now it seems that a typed table has no simple way to omit certain columns from the payload. Omitting them from the row class instance creation results in them being null in the payload, even if using e.g. these on the field:

[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
// or:
[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]

Right now it seems the solution is either to use a separate class (yikes) or to resort to untyped tables.

[skedwards88]

For the docs: Once this is fixed, update the row/rows parameter description for tables findOne/find to not say "If you use a custom class, any unspecified columns are set to null."