We are actually looking for g.brush elements in the 1D case.
Add a test to verify that a 1D brush gets properly removed.
Properly uninstall the 1D brush.
Move the strum code into a anonymous function wrapper
Unify the strum mode with 1D and None.

We had a parcoords.strummable() function, which would enable strumming.
Now, we enable strumming in the same way as for 1D strumming.
Only add a canvas for strums when strumming is enabled.
Generalize the brushMode topic code a bit.
Add a test to verify that 2D-strums adds the required canvas.
Add a tests for the axesreorder handler of 2D strum

It shouldn't be set by default. However, 2D strums sets one to update the
strums properly when axes are reordered.
Use install, as we did in the '1D-axes' case.
Implement brushReset for 2D-strums
Test if the g#strums element is added for 2D-strums
Add a brush toggle button in the strums example as well.
Add some test to ensure that 2D-strums is properly uninstalled.
Properly uninstall 2D strums.

This fixes the tests.