Just include the AWMC base map for now, until the pipine is in place for the overlays.
Swaps out Chosen for Select2 on exhibit add/edit form.
Revert "Swaps out Chosen for Select2 on exhibit add/edit form."

This reverts commit 5b4aba56eee2aeae2fdbada12a414f56c9039d14.
Adds isBaseLayer attributes to the layer definitions.