Visual feedback while request is in process

[asherber]

When I send a request, there is no immediate visual feedback that anything is happening, aside from the "Waiting" text in the status bar. Some requests can take several seconds or longer to complete, and it would be nice to have some indicator that the request is in process. 

I suggest:

1. Clear the Response pane when a new request is sent.
2. Change the cursor to a wait cursor until the new response has finished rendering or until an error is thrown.

[jaimehrubiks]

Or at least change the tab title from "Response(3012ms)" to "Waiting for response" or similar, that would also work great