Added clarity to a note about linux limits

I found the note at http://docs.turbulenz.com/starter/getting_started_guide.html#creating-a-turbulenz-application about Linux's canvas limitation to be ambiguous (was it the local server or the client). Knowing *now* what it is makes it all very clear, but for people who are first seeing the docs it could be confusing for them as well. Explicit is better than implicit, so they say.