Add dependency on Breeze

Breeze provides high-performance linear algebra classes and routines.
Since one if its dependencies, netlib-java, requires system properties
to be set on some platforms, this commit also enables them to be
specified in application.conf.
Use Breeze matrices for interpolation

This significantly improves interpolation performance.  While there is
still overhead in converting the results back to immutable Vectors, it
is comparable to the current cost of color-mapping.