Upgrades in next Linux VM update

Pull request to track the documentation of version upgrades coming with next Linux VM update + related blog post. Branch created in main repository to allow contributions from everybody.

cookbook changes, diff used: https://github.com/travis-ci/travis-cookbooks/compare/63d9784f08297cbeacda9dd410d3db80215eb1b0...926e5116307b4a2c5cf2ab9655fc1389dea60ef8

**Ready and documented:**
* Clang 3.3, see travis-ci/travis-cookbooks#212
* JDK 8, see travis-ci/travis-cookbooks#236
* Maven 3.1, see travis-ci/travis-cookbooks#229
* Leiningen 2.3.1
* Gradle 1.8, see travis-ci/travis-cookbooks@562f7154a5f49e53b6045b5be48c91542213b6c4
* Erlang / OTP changes documented in #364 **+ more recent stuff**
* PosgreSQL addon (multiple versions) documented in #369 (TBD, update travis-ci/travis-ci#1008). + PostGIS 2.1
* Update for Portuguese Translation: #374

**Changes that only appears on blog post:**

* All Language Updates
* Riak 1.4.2-1, now from apt repository (see travis-ci/travis-cookbooks#240 and travis-ci/travis-ci#1090)
* Neo4J Sever 1.9.4
* Cassandra 2.0.2 + Cassandra fix in travis-build (ask @roidrage)
* ElasticSearch 0.90.5
* PhantomJS 1.9.2 (from 1.9.1)
* new php module: kerberos, imap, imap-ssl
* Python Changes: python 2.5 out, distribute out (distribute_setup renamed to setuptools/ez_setup), virtualenv 1.10.1
* Scala: new pre-installed stuff (0.13, boot presetup) and change in sbt-extras defaults behavior!

**Silent Changes**

* JDK switcher new warnings: travis-ci/travis-ci/issues/1291
* announce libevent and md5deep introduction?
* RAMdisk increased a bit ~200M... (768m - 70m - 512m)
* Update to RVM 1.22 **1.23? pending joshk upcoming update** (latest minor)

**Open Questions**
* I've seen that cassandra.conf_dir changed... OK?

**Resolved Problems:**
* service autostart issues (memcached, redis-server)
* cassandra hostname configuration
* maven3 ubuntu bug

**Planned stuff / Known Issues:**
* Gradle/JDK8 bug
* outdated gcc 4.6 (gcc 4.8 will come soon)