[FreifunkFranken/firmware] 2e0c1c: Update README.md

[Oliver Voelker]

  Branch: refs/heads/master
  Home:   https://github.com/FreifunkFranken/firmware
  Commit: 2e0c1c24dd4ca1ef8d79a7cb956d74da02947155
      https://github.com/FreifunkFranken/firmware/commit/2e0c1c24dd4ca1ef8d79a7cb956d74da02947155
  Author: Oliver Voelker <magenbrot at users.noreply.github.com>
  Date:   2014-10-27 (Mon, 27 Oct 2014)

  Changed paths:
    M README.md

  Log Message:
  -----------
  Update README.md

Das Paket build-essential sollte auch installiert sein.