Add support for streaming

[greg0ire]

See jdorn/sql-formatter#68

[goetas]

This seems possible now thanks to #48

[mvorisek]

Tokens can be streamed, but formatting cannot as we might need up too complete lookbehind/lookahead.

However, if you want to support piping as requested in jdorn/sql-formatter#68, tokenization can be streamed on token basic and formatting done on query basic with separating detected using these two conditions

sql-formatter/src/SqlFormatter.php

Lines 120 to 122 in 027ca22

	if ($indentLevel === 0) {
	$prevNotWhitespaceToken = $cursor->subCursor()->previous(Token::TOKEN_TYPE_WHITESPACE);
	if ($prevNotWhitespaceToken !== null && $prevNotWhitespaceToken->value() === ';') {

(semicolon + zero indentation level).