added a function to check if we're on the configured sign-up page or not
Merge pull request #19 from wluo/freebird

added a function to check if we're on the configured sign-up page or not
removed a debug logging call; return early from is_signup() if we already have the value of $this->is_signup
Merge pull request #21 from wluo/freebird

removed a debug logging call
Merge pull request #20 from GigaOM/freebird

implemented the is_signup() function