Add icons

These are Arduino icons in various formats that can be used by
redistributors in menus etc.

These icons were taken from the Debian package, version 1:1.0.5+dfsg2-1.
According to the copyright file in there, all icons are licensed under
the GPL-2+.
Add .ino mime type info for Linux

This file is not installed by the ant build, but is intended for use by
Linux distributions.

The actual file was taken from the Debian package, version
1:1.0.5+dfsg2-1 and is licensed under the GPL-2+. It was only modified
to remove a FIXME comment that is no longer relevant.
Add arduino.desktop file for Linux

This file is not installed by the ant build, but is intended for use by
Linux distributions.

The actual file was taken from the Debian package, version
1:1.0.5+dfsg2-1 and is licensed under the GPL-2+. The GenericName,
Comment and Categories fields were changed to better reflect the Arduino
program and Desktop specification.
In boards.txt, rename atmega328diecimila to diecimila

This board has a "cpu" submenu to select either atmega328 or atmega168,
so it does not make sense to put atmega328 in the main board name.
Add manual page

This adds a description of commandline options, files used and some
preferences in proper Unix manpage format. It is written in asciidoc,
which can easily be converted to both a native troff manpage, or HTML
(the latter can be done by github on-demand).
Merge pull request #1727 from matthijskooijman/ide-1.5.x-linuxstuff

Ide 1.5.x linuxstuff and manpage