need functions to write descriptions to metatable

[joethorley]

something like

rws_describe.character(x, column, description)

which is vectored and must be in table

rws_describe.data.frame(x)
which requires columns Table and Column and Description and simply calls rws_describe.character

[joethorley]

implemented rws_describe_sqlite_meta() just need to test

[joethorley]

done