Formatting changes

[joeyadams]

This fixes some formatting issues that annoyed me:

• Use more intuitive qualified names for Data.ByteString modules

• Clean up whitespace, particularly around do and where. The most unsightly lines were:

  sendCommand (SMTPC conn _) meth =
  do bsPutCrLf conn command
   parseResponse conn
  where command = case meth of
                  (HELO param) -> "HELO " <> param
                  (EHLO param) -> "EHLO " <> param
                  ...

These commits change nothing but formatting.

[jhickner]

Thanks!