[fix] Adding negative conditions for NULL/Array and fix integer

Allow the [!] flag to make "column NOT NULL" if null given, "column NOT
IN (1, 2, 3, ...)" if array given. Then fix quoting for integer values.
[develop] Fix #37 SQLite connection issue
[develop] Tiny code style fix
[feature] Multiple insert

Suggested by @josegustavo on issue #48
[fix] Fix #50 JOIN condition for select bug
Update Readme
[fix] Code style fix & compatability update
[release] Medoo 0.9