PETSc 3.5.1 with intel 2014b

Plus dependencies
Needs https://github.com/hpcugent/easybuild-easyblocks/pull/446
and https://github.com/hpcugent/easybuild-framework/pull/987


There are:
```
https://launchpad.net/%(namelower)s/%(version_major_minor)s/%(version)s/+download/
https://launchpad.net/%(namelower)s/%(version_major_minor)s.x/%(version)s/+download/
https://launchpad.net/%(namelower)s/%(version_major_minor)s.x/release-%(version_major_minor)s/+download/
https://launchpad.net/%(namelower)s/%(version_major_minor)s/%(version_major_minor)s/+download/
```
The first one is the most used one. It seems that only FIAT and DOLFIN use the ```.x``` version.

@boegel we already give multiple download url's on some packages? Why not give a list for it to try?