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

Mlt handler support

add pecl_http support