Signals performance tests litter output buffer

[k1o0]

Related to #12, when signals performance tests are run the result is hundreds of lines of

Deleting net(0)
.**net.delete**

There is no way to turn this off as it's hardcoded into Chris' MEX functions. Suggestion:
run performance tests last and turn off output beforehand with diary off.

[k1o0]

It may be possible, albeit hacky, to open the log file within runAllTests and delete these lines.