* Added the DLE EOT querying command.
Added a function to check whether the printer is online or not, as well
as a reading method for USB printers.
* Update AUTHORS
* Add entry to .mailmap
* currently USB only
The file-printer did not automatically flush and thus behaved
differently to the other printer-classes.
Now the default behaviour is to flush after every call of _raw(). This
can be disabled by calling the file-printer with auto_flush=False.
fixes#106