download results only if IDA compatible

[danv61]

PR #1633

• fixed problem where non-langevin solver results threw exception while trying to interpret as langevin data.
  • download results only if IDA compatible
  • wrapper around langevin batch results, can add utility functions without creating incompatibility between proxy and stub
  • the batch result set object may now be null
• change default client-side configuration of vcell.enableSpringSaLaD to true.