Minor changes, and prompt changes.

I have three small commits for your consideration.

The first just moves the output of the newline to happen immediately when a command is executed. The motivation is that otherwise there is no feedback until the interpreter starts producing output. The second commit is to only call basic-save-buffer again if stylish is actually applied.

The third commit might be a bit more dubious; it changes the prompt handling slightly, to fix two problems. The first problem is that often -- but not always -- you get a blank line after the output before the next prompt. The second problem is that if the output doesn't end in a newline (e.g. putStr "xyz") then the prompt finding goes awry.

I'm not an expert in haskell-mode, so I'm happy to accept any criticism. (: