Let parse_str() parse more than max_input_vars args

It is somewhat unintuitive that parse_str() is subject to the max_input_vars limitation and there are sites that use parse_str() to parse things that aren't directly coming from user query args. There arr two ways to solve this. We could add an optional max_vars arg something along these lines: https://gist.github.com/2038870 The other way to solve this would be to make max_input_vars PHP_INI_ALL and then just let people ini_set() their way around the limit. The one drawback with the optional arg approach is that since parse_str() is a thin layer on top of the query string parser, the error if you exceed the passed max_vars talks about the ini setting which in this case wouldn't really be correct and fixing that would be complicated. -Rasmus