NeatlineMaps hasn't been migrated for Omeka 2.x, but you don't really need it for Neatline. What the plugin does is allow you to upload a Geotiff to a Geoserver instance, but because of how large Geotiffs generally are, it quickly becomes more of a hinderance than help. PHP (generally) has a setting that limits the size of a file upload, which turns out to be a setting a lot of people can't change in the
php.ini of their server.
There is a much simpler way of uploading Geotiffs to Geoserver that doesn't require PHP in the mix with the REST services for Geoserver with the
curl utility. As long as your tiff is less than 2Gb, you can do something along these lines to efficiently add a tiff to Geoserver, creating all of the web services that go along with it. First, create a CoverageStore (if it doesn't exist); I'll use 'neatline' as the default:
curl -u admin:geoserver -v -XPOST -H "Content-Type: application/xml" -d ''<coverageStore><name>neatline</name><workspace>neatline</workspace><enabled>true</enabled></coverageStore>" http://yourserver.8080/geoserver/rest/workspaces/neatline/coveragestores
Then, you can upload the tif(s) to the server with. Let's say you have a map named "virginia.tiff" that you've georeferenced, you can put it on the server with this:
curl -u admin:geoserver -v -XPUT -H "Content-type: image/tiff" --databinary @virginia.tif http://yourserver:8080/geoserver/rest/workspaces/neatline/coveragestores/virginia/file.geotiff
After the file is finished uploading, Geoserver will create it's web services for use in Neatline (under the Neatline item style tab; look for WMS). In those fields, fill in the WMS address for your server:
WMS Address: http://yourserver:8080/geoserver/wms
Layer Name: neatline:virginia
You will always view the layer names by going to your Geoserver instance, and clicking on the "Layer Preview" link too. Basically this lists all the layers you have access to (and can use in Neatline). You can also double-check the layer name by looking at the "OpenLayers" view and in the URL, look at the layers parameter.
We're in the process of wrapping much of this process into a utility (https://github.com/scholarslab/Geoloader) to ease this workflow, but this is in Ruby (which may also be another barrier). I think we need to provide some documentation on this somewhere, but to make sure I address your specific needs in getting data to Geoserver, could you tell me what operating system you use?
Hope this helps,