Adds data refreshing signal.

I need to figure out my whitespace settings so so much noise doesn't come through...I have Sublime setup to auto trim extra whitespace.

Anyhow, this request adds in a data_refreshing signal.  This signal is useful if we want to give some indication that there is something happening, even if it's in the background.  I use it to run some small indicators in our UI's.  I hope it's useful!