Added forceful evaluation of top-level lazy sequences. This allows us to implement printing in our REPL. One inconsistency of note between minirepl and the regular clojure repl is that definition of lazy sequences in a regular repl does not forcefully evaluate the lazy sequence. This is because in a regular REPL, a definition returns the var, rather than the lazy sequence itself. We have to figure out some way of preventing this forceful evaluation. This may be fixed by the recent addition of vars to clojurescript? More research required.