Removed requirement for PHP method bodies to be compound statements to simplify translation
Added test scenario for PHP 'for' loop with no braces/compound statement for body
Fixed issue with PHP function and class declarations inside 'foreach (...) {...}' loops being hoisted
Fixed support for PHP 'foreach' loops with bodies not compound statements/wrapped in braces
Simplified interpretFunction() by removing now-unnecessary statement node list handling

- All function bodies are now one statement node, using N_COMPOUND_STATEMENT for grouping
Added support for binding variables for PHP closures with the 'use' phrase

- Refactored scope chain setup to be a 'call stack' for correctness