✨ index access

[kkharji]

Purpose

Make it possible to access sqlite.tbl operations using index access:

for example:

localkvtable=tbl("kvtable", {
key= { "text", primary=true, required=true, unique=true },
value="integer",
}, db)
--- access/insert-to/remove using primary keykvtable.a= { value=1 }
kvtable.a=nil--- access/update a row field value kvtable.a.value=2kvtable.a.value=nil--- sets a key field value without creating the key firstkvtable["some key with spaces :D"].value=4

closes#98

[kkharji]

... to be continued sometime next week. reviews are welcomed.