FIX: Keep axes brushable and reorderable on updates

When I configure my parcoords to be reorderable, and I call updateAxes() at
some point, the axes wouldn't be reorderable afterwards.

Same for brushable.
Add a brushend event.

When dealing with many observations and when trying to connect pc to other kinds
of views, it is more desirable to update views only on brushend. Updating on
each brush event causes a lot of unnecessary rendering in other linked views.
Add a function to retrieve current brush extents.

I need this for an application I'm working on. However, this can also serve as a
starting point for fixing the brush resets on resize. I'll have a look at that
soon.
Fixed an axes hiding issue.

Axis hiding didn't work before calling bundleDimension() or render()
default is a reserved keyword in JavaScript

Naming a property default is okayish, though it is a reserved keyword in
javascript. Let's make some people's editors happier by quoting it when
accessing this property.

Fixes #50
Remove underscore.js dependency. Fixes #49
Fix brushing behavior when the last brush is removed

When the last brush is removed we don't want to return the full data set
when. Actually, when there are no axes brushed, by definition, no items
are selected. So, let's avoid the filtering and just return false.
Remove obsolete scratsch directory
Get rid of d3 submodule.

There is no need to have the full d3 source in the repo. Actually, it is
only required to make the examples work, so add the dep like any of the
other deps of the examples.
Move data and lib into the examples directory.

Both dirs where there just for the examples to work, so let's keep them in
there and clean-up the top-level directory of the repo a bit.

#58
Whoops, Remove vim swp file
Get rid of .gitmodules all together
version increment, homepage link fixes