added rescore query
added weight setters
added rescore test stubs
Finished rescore and tests
fixed naming and added changes to changes.txt
added elasticsearch test for rescore
fixed changes.txt conflict
fixed naming convention again
restructured rescore classes and added setRescore to both Query and Search and the accompanying tests
updated changes.txt
removed some outdated changes
Implement \ArrayAccess on Elastica\ResultSet

To ease customisation and access to the Results,
we can now get the results manualy.

Not sure about offsetUnset, maybe it should just throw an Exception
Add documentation and tests
Support isset() on results
Nested filter supports now the setFilter method.

When using elastica to perform a search using only filters there was no method
to set an AbstractFilter to the nested Filter so I've added the setFilter method.
Add InvalidException when trying to mess the Result object

refs #445
Merge branch 'master' into array-access-results

Conflicts:
	changes.txt
Merge pull request #445 from damienalexandre/array-access-results

Implement \ArrayAccess on Elastica\ResultSet
When there is no valid connection left, don't retry the request but throw the real error.
Added assertion for __get() and __isset() methods.