Support redirection of test output

[whart222]

pyutilib.testdriver should support options for redirecting test output and error to alternative locations. Currently, the test output is logged to a file and then deleted(?). The driver should support options for:

• saving all the output to a user-specified location (dir or filename?)
• dynamically output to the console (so someone can watch the job run "live" -- e.g., through Hudson)

Another useful option would be to echo a character to the console for every so many lines or bytes captured on the stdout/stderr (so that people following a job can know that the job is progressing and not just hung). That could keep the data archived data in Hudson smaller -- and if they are running in Hudson, they can always browse the workspace to see the current status of the build log file.