[eclipse] Fixing the invalid test of the SARL version supported by a selected SRE.

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[docs] Explain how to launch agents programmatically.

see #229

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[eclipse] Avoid invalid error messages when adding SRE.

Create a fresh copy of the SRE description when selecting a Jar file.

see #226

Signed-off-by: Stéphane Galland <galland@arakhne.org>