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.

Author: matthijskooijman

build/linux/dist/arduino.desktop

@@ -0,0 +1,11 @@
+[Desktop Entry]
+Type=Application
+Name=Arduino IDE
+GenericName=Integrated Development Environment
+Comment=An IDE for Arduino-compatible electronics prototyping platforms
+Exec=arduino
+Icon=arduino
+Terminal=false
+Categories=Development;IDE;Electronics;
+MimeType=text/x-arduino
+Keywords=embedded electronics;electronics;avr;microcontroller;