Document memory limitations

[senderle]

Adjusting the amount of memory available to the JVM is challenging, especially now that we're supplying a pre-packaged version with its own JVM. When users run into memory limits, the error messages they'll receive are limited and confusing, and the best way to deal with this problem isn't obvious.

There needs to be better documentation laying out the problem and possible solutions. For intrepid readers, there's some basic, easily digestible information on stackoverflow.