CDM fixes

Put back the use of writer. For some reason, this seemed to work before
my commit.

Also scale up the test to 10x10 traces.
Naive dynamic time warping implementation

Using clojure.core/cache instead of a proper dynamic programming
approach. Still, it was quick to implement and it does 10x10 in 2.7
seconds; but that's way too long to even handle 100x100, let alone 10^6.