dynamically generate analysis dialog

analysis-app now loads its analyses from the TreeStore and
dynamically populates the dialog that it presents to the user.

The analyses are loaded into the TreeStore by running
import_analyses.py, located in ProjectManager/tangelo.
use arborapi's new header functionality

When populating a list of columns, we can now query arborapi
for just the header row of the table, rather than downloading
the entire table unnecessarily.
Merge branch 'master' of https://github.com/arborworkflows/ArborWebApps