Optimizers fix

Hi,

I added support for 2 params calls of trim, ltrim and rtrim functions. Otherwise it's impossible to compile Phalcon 2 code.

PS. Do you consider benefits of getting Phalcon 2.0 codebase to state that people will be able to compile it? I believe that is the MOST important thing to get people involved - otherwise they won't create PRs/contribute for code that they cannot compile. I'm pointing this one as I received a screencast link today(it's really good - congratulations btw.).

PS. PS. Next compilation error is:
PHP Warning:  PHP Startup: Unable to load dynamic library '/var/www/cphalcon/ext/modules/phalcon.so' - /var/www/cphalcon/ext/modules/phalcon.so: undefined symbol: phalcon_set_symbol in Unknown on line 0