Update M2E P2 repository URL

To workaround bug 407797 [1], main M2E P2 repository does not
reference M2E 1.3.x and earlier versions any more. The old versions
are still available but need to be installed using version-specific
repository URL [2].

[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=407797
[2] http://wiki.eclipse.org/M2E_updatesite_and_gittags#m2e_releases
Add support for Eclipse Kepler as a target platform

[1] http://www.eclipse.org/kepler/
Reduce amount of build logs

Ubuntu package updates are rarely cause problems, so we don't need all
these details on what's going on during update.
Merge pull request #161 from manandbytes/travis-ci

[releng] Introduce support for Eclipse Kepler