v2.13.0

Feature

• reworked UI
• allow fsaverage grid to be toggled on/off
• disable surface face selection (until it becomes fully supported)
• allow feature to be downloaded
• main download button also downloads selected feature
• added javascript disabled page

Behind the scene

• ported the backend to use python rather than nodejs

Bugfixes

• fix URL encoded annotations
• improved reliability of URL encoding of viewer state