Fix small issue with log scrolling in flash

The scrolling of the `log` textfield was kind of broken on the flash target - as soon as the number of lines exceeded `MAX_LOG_LINES` (which is 200), the textfield would get at about half of its height / lines (around line 109 I think). Setting it to `maxScrollV` seems to fix it.

There's another issue regarding scrolling on non-flash-targets (windows at least), the scrolling of the textfield lags behind by a couple of lines. I haven't really been able to figure out how to fix that, though.