Standard constants as part of the lexer

The constants true, false and null are used very often. Unfortunately, every usage of either of these constants invokes a constant lookup. There is no problem with this, constant lookups are fast, but I nevertheless implemented these constants directly in the lexer to avoid these lookups. I'd be glad to see this change in 5.4 as the performance enhancement would be a steal. I've also added a new OP code to hard-code count() and strlen() which improves the performance by ~800%. This is nice, but limits the usage of count() and strlen() as method name - if no further changes will be made at the parser. I would rather see a optimization for every function call in 5.4.x. I'll take a look at this soon, maybe I can provide a patch for this, too. What do you think about the constants optimization? Unfortunateley, I've broken the power cable of my macbook and have to wait for a new one. I'll deliver in addition the patch if you like the idea. Robert