EyeServer: add support for setting name of EDF file

[joschaschmiedt]

The EyeServer.Start method is currently always called with 'tmp.edf' as filename:

ARCADE/arcade/Core/launch_processes.m

Line 98 in 79dab2a

EyeServer.Start('tmp.edf')

As a consequence old data is always overwritten. This has the advantage that the Eyelink disk will never fill, but makes it impossible to retreive old data from the Eyelink PC, which may somtimes be useful. We should therefore probably provide a user setting to change this behavior.