0.1.0: architecture almost finsished and can run sql now

[Veeupup]

Signed-off-by: Veeupup code@tanweime.com

architecture almost finsished and can run sql just like:

use how_query_engine_work::Result;
use how_query_engine_work::NaiveDB;

fn main() -> Result<()> {
    let mut db = NaiveDB::default();

    db.create_csv_table("t1", "test_data.csv")?;

    let ret = db.run_sql("select id, name from t1")?;

    println!("ret: {:?}", ret);

    Ok(())
}