Ignore .venv virtualenv location (which is suggested name in install notes)
Correct section id so that nav links work as expected
Add an 'intersects' query type

This new query type finds any areas that intersect the given
area.
Indicate that the generic import script also works with GeoJSON files
Add a command for deactivating a generation
Add a command to delete areas for a new (inactive) generation
Fix two small errors in mapit_delete_areas_from_new_generation
Comparisons of generations should be done based on id

Using == to test equality of Generation objects is fine,
but comparisons like < use the meaningless default
comparator.  Compare based on the id column instead.
Fix construction of an unexpected Exception message
Add an option to create a new area if polygons have changed

The default behaviour of the generic import script, if it finds
an area with the same name / code in a previous generation, is
to replace the polygons associated with that area.

However, we may want alternative behaviour, where if a new
generation of data has a changed boundary for an area whose
name / code remains the same, we create a new area with those
polygons and preserve the previous one.  This commit introduces
that change with the --preserve option.

Fixes #52
Add a verbose option and more logging to the generic import script

Particularly with the --preserve option, it can be useful to see
more detail about what would happen to each boundary.
Add a simple command to print all areas in all generations
Make sure that areas with the same name have the same colour

The simplest way to do this is to reseed the random number generator
based on the name of the area before picking a random hue.
mapit_import: show a percentage representing change in the boundaries

When --verbose is specified, this will also show the percentage
difference between (a) the area of the symmetric difference
between the old boundary and the new boundary and (b) the area
of the old boundary.  This is a reasonable indication of how
much an area with the same name / code has changed from one
generation to the next.
Tidy up whitespace of command output
document alternatives to low-volume non-commercial use
Add new CPW type for community wards.
Document that 2012-10 Boundary-Line didn't need anything.
Merge branch 'community-wards'
Fix typo.