We were binding as blobs which we could read back as strings,
but which didn't match string inputs! Very confusing!
Always bind as strings.
For the empty rows case: don't return the affected row count
unless the query has 0 columns, as we otherwise cannot distinguish
between no matching results and a single column with 0.
A bit of a big commit because I wanted sqlite queries to run
async and there isn't a sane way to tell in mlua whether a
given context is safe to yield for an await, which meant making
every case where we call into lua be fully async.
This adds a simple but powerful binding to sqlite that performs
its IO in a blocking tokio thread pool, and returns the results
back to lua.
There is no implicit caching of queries, and no implicit connection
pooling.
Wez Furlong