Fix incompatibilities due to PyBossa upgrade

[othieno]

Currently, the following pages are broken due to the changes introduced in PyBossa:

• [x] Updating projects (/project//update) [Fixed in 14d9d0d]
• [x] Importing project tasks (/project//tasks/import) [Fixed in 8cba4a8]
• [x] Flushing task runs (/geotagx/project//flush_task_runs) [Fixed in geotagx/geotagx-plugin@795cbb4]
• [x] Exporting summaries as GeoJSON (/geotagx/export/category//GeoJSON) [Fixed in geotagx/geotagx-plugin@25f37b3]

[othieno]

For the curious: pybossa/pybossa-default-theme@c83214c.