Adding editabilit to training cohorts
Adding Bootstrap styling.

1.  Generic page layout now references Bootstrap files delivered via CDN.
2.  Page layouts now use Bootstrap CSS classes.
Simplify permissions: if a user can edit, she can edit everything.
Merge branch 'changing-permission-model' into adding-cohorts
Simplifying permission model: if a user can edit, she can edit everything
Merge pull request #53 from gvwilson/changing-permission-model

Simplify permissions: if a user can edit, she can edit everything.
Merge pull request #50 from gvwilson/adding-bootstrap

Adding Bootstrap styling.
Merge pull request #49 from gvwilson/adding-cohorts

Adding editability to training cohorts
Adding airports to pages.

1.  Adding classes needed for Django form creation.
2.  Adding URLs for forms and pages.
3.  Putting editable fields for airports and other objects into free-standing variables.
4.  Added views.
5.  Added headings to views of other "all_xxx.html" pages.
Starting to work on tasks
Merge branch 'adding-airports' into adding-tasks
Adding display of tasks - editing still fails.

1.  Added usual views for table-based display and forms-based editing.
2.  Link to edit tasks fails - Django complains that it cannot look up the task, but is being given the id.
Set pk_url_kwarg on tasks view so django knows where to look for task
id.
Get the right reverse url for a task object using kwargs.
Make the edit url for a task object a bit more friendly.
Using simpler anonymization for imported data
Line too long in Task's get_absolute_url method
Added tests for the new Task views
Format person a little better if email is not set
Added pagination to the all_events view/template.