Codepage of input parameters

I ran to problems with codepage of input parameters. Column values in recordsets are converted by iconv with collation encoding specified by metadata. That is not happening for input parameters, so I made changes to make this possible.

You can now set default codepage of input parameters as a config parameter `parametersCodepage`.

```javascript
var connection = new Connection({
	userName: '...'
	password: '...'
	server: '...'
	options:
		parametersCodepage: 'windows-1250'
});
```