Radial dam-break problem for 2D shallow water equations.

Subdirectory 1drad contains code to solve 1d radially symmetric equations
on a fine grid.  First run this code.

After running 2d code, with same set of output times as in 1drad,
use the following matlab commands to compare the two:

>> plotclaw2
>>  [ advance to desired frame]
>> error2drad

Note: this sets PlotType=4 to give a scatter plot of q as a function of r.