Make lexer return AST nodes

Remove dead code

Replicate old linenos for class binding

Fix bugs

Fix leaks

Must find a good way to handle constant expressions...

Use arena allocator (currently leaky!)

Resolve futher interning issues

Not sure if this is the right way to do it ...

Fix interning bug

Add call_user_func optimization

Implement call_user_func_array optimization

Implement ZEND_DEFINED optimization

Implement ZEND_TYPE_CHECK optimization

Implement ZEND_STRLEN optimization

CT bind args before unpack

Port ZEND_BIND_GLOBAL optimization

Remove declare_stack

Dead code

Implement declare()

Handle __halt_compiler()

__halt_compiler() without haling compiler

Add NS error checks

Those can probably be implemented in a better way now...

Discard NS doc comments

Code cleanup

Fix namespace\, maybe

Port top level stmt

Problem: namespace\foo no longer works :/