Remove internal Timeout for matrix tests.

[petevg]

This is an Alexandrian solution to our "matrix is too green" bug.
(#123)

It also makes things a lot nicer in general. External tools calling
matrix still have to include a timeout, because the existing matrix
timeout only covered hangs during a test run; hangs during setup
or teardown could still lead to a hung matrix. And External tools with
a timeout still have to worry about cleaning up matrix models; having an
internal timeout cleanup that only helps in some cases isn't necessary.

This also simplifies the code, and removes a command line param. A win
all around, I think.

@johnsca @kwmonroe

[kwmonroe]

+1 assuming travis completes successfully.