Wrap grid in atom to hide from parser.
Wrap grid in atom to hide from parser.

This is to avoid the slowness in om next when transacting a very
large value into the application state (see omcljs/om#556). Since
we never need to query *within* these grid values, we don't need
om to go delving inside them to do its indexing.

glv/snergly,glv/snergly