[feature/twig] Forgot to set up $config in node/php.php

PHPBB3-11598
[feature/twig] Fix alter_block_array to correctly set S_ROW_COUNT

PHPBB3-11598
[feature/twig] Set S_ROW_NUM in context also (previously was a hack in filter)

PHPBB3-11598
[feature/twig] Replace BEGIN with Twig for using Lexer

No longer using the begin tokenparser/node as it did not allow proper
handling of <!-- BEGIN !foo, <!-- BEGIN foo(0,2). Now the lexer will
use regular expressions to handle that correctly and replace it with Twig's
for token

Also fixing <!-- IF .foo as I discovered it evaluates to if sizeof(foo)

PHPBB3-11598