[eclipse] Add a manager of installed SARL runtime environments.

see #167.

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[eclipse] Add extension points for SARL Runtime environments.

Two extension points are added:
* sreInstallations: provides implementations of ISREInstall.
* sreInstallPages: provides configuration pages for a ISREInstall.

see #167.

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[eclipse] Fixing the NLS messages.

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[eclipse] Create independent component for selecting the SRE.

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