Added lots of optimizations related to expression optimization. Combining adjacent expression statements into a single statement means more if-, for-, and while-statements can get rid of the curly-braces. Then more if-statements can be converted to expressions, and more expressions can be combined with return- and for-statements. Moving functions to the top of their scopes, followed by var-statements, provides more opportunities for expression-combination. Added command-line option to remove all comments, even if they are "important": -comments:none (-comments:important is still the default behavior).