Add initial line, delimiter, getters, setters

Added parameters:
 - initial_line (The line from which start parsing data)
 - delimiter (The values delimiter - e.g. ',' or ';')

Added public setters and private getters.
Is now possible to use the library like this:
$this->csvimport
	->filepath('/path/to/file.csv')
	->detect_line_endings(TRUE)
	->initial_line(10)
	->delimiter(';')
	->column_headers(array('id', 'name', 'company', 'phone'));
$data = $this->csvimport->get_array();

Or in the old way (with the two new parameters added):
$this->csvimport->get_array('a.csv', array('id', 'sku'), TRUE, 0, ';');