Add charset options lc_type and lc_decode to createConnection

[mjschutz]

Hi.

I made changes to support options on createConnection to change lc_type and a lc_decode function to decode the result buffer to string. Example:

let connection = Firebird.createConnection({ lc_type: 'WIN1252', lc_decode: (data) => iconv.decode(data, 'windows-1252') });

I run tests here and the code is working fine (node 12), this will probably resolve the issues #9 and #87

[mjschutz]

I will check the problem with the assync version of connection, and commit a fix.