Nearly working documentation pipeline with maps.

The documentation pipeline works with the server locaiton hardcoded.

This commit:

 - 'make all' now copies the 'gmaps_views.js' file from the main gmaps
   directory.
 - modifies the way the map is generated in the final html file to only
   occur when the document is loaded.
 - moves the DomWidgetModel definition out of the ipython file into the
   manager file. The ipython file now just defines the namespace, just
   like the file it is emulating.
 - a couple of fixes to the requirejs.config declaration.
Added custom nbconvert to resolve notebook paths.

This commit adds a custom nbconvert script to the docs section to make
sure that the HTML documentation is built with the correct path.