Neater version of burgers1.red, with alternative that computes
df(u^2,x)/2 instead of u*df(u,x) - no difference. The problem still lies
with the u_11 term from u :=
u_00+gamma*u_10+epsilon*u_01+gamma*epsilon*u_11, since [u'_11]_j != 0.
Are we integrating correctly to get u_11? Do we need to modify the IBC
to include an epsilon term?