fix issue 27

Fixes issue 27 by adding a timer and if we havent received the report version or query firmware ask for it.  I think this addresses this comment https://github.com/jgautier/firmata/issues/29#issuecomment-20922076 @rwldrn @soundanalogous @brainrape please review and test.  I tested this by commenting out these two lines https://github.com/firmata/arduino/blob/master/Firmata.cpp#L72-L73 uploading standard firmata and verifying examples/blink.js still works.