Following symlinks in arduino launch script for Linux.

Updating version to 0021.

Updating version to 0020.

Tagging release 0019.

Tagging release 0018.

Tagging Arduino 0017 release.

Tagging release 0016 (a little late, but it should still be right).

Tagging release 0015.

Tagging release 0014.

tagging release 0013