option to trigger all events on start

[hramrach]

I want an option to trigger all events when I start watchr as if all the watched files have been modified.

I hacked this feature into my copy of watchr but I found that with the current event interface if I fire modification event for both source file and its test file the tests are run twice. watchr sees this as two different events and the fact they execute the same command in the end is hidden from watchr.