Improved testcoverage for spellcheck

Now per field highlighting options can be added.

Merge branches 'develop', 'feature/analysis' and 'master' of github.com:basdenooijer/solarium into develop

Add support for Distributed Search (shards)

- added unittests

- small phpdoc fixes for MLT

- small style / phpdoc fixes

- renamed options because the usage of dots conflicts with some config file formats
- added getters and setters for more MLT options

- small style and phpdoc fixes

- now extends the select query builder to prevent duplicate code

- added new examples for MLT and peclhttp

Lots of style, comment and copyright modification