Fixes issue with missing keystrokes

This fix addresses a bug where the old ascii_println function misses the first and last character of each line. Teensyduino/Arduino IDE appears to have added a `Keyboard` class that has a `println` method. This method seems to reliably send all keystrokes to the target and at a seemingly faster rate.
Merge pull request #51 from allfro/master

Fixes issue with missing keystrokes