stacktrace tests
stack trace implementation in the VM
compiler forks (enabled by -DSTACKTRACES) to ensure exceptions get traced properly
use "vm" module sandbox on nodejs for requiring vanilla js modules to get correct filenames in stacktraces
Write stacktrace information to `err.message`, as `err.stack` can't be reliably used (it has no effect in chrome / firefox, for starters)
Preserve newlines in errors reported by xbrowser/console
stacktraces cleanup
compiled oni-apollo-* with stacktraces (in a separate commit to ease merging)