check if current type exists in Index
@see http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/indices-types-exists.html#indices-types-exists
check if current type exists in Index - changes.txt
check if current type exists in Index - phpunit test
Merge remote branch 'upstream/master'

Conflicts:
	changes.txt
Elastica_Type::exists()  - added index->refresh() after document add in unit tests
Merge pull request #481 from krzaczek/master

check if current type exists in Index
Issue #490: Set Elastica\Query\FunctionScore::DECAY_EXPONENTIAL to "exp" instead of "exponential"
Remove wrong documentation for "no limit" #496
Update to elasticsearch 0.90.7
Modified source from Elastica\Prefix class
Added Regexp Unit test.
Merge pull request #495 from trash80/regexp-filter

Modified source from Elastica\Prefix class
Update geocluster facet plugin to v0.0.9
Make addition to changes.txt
Merge pull request #499 from jlinn/geocluster-facet

Update geocluster facet plugin to v0.0.9
Update README with dependencies
Added "required" column to README
Raw array query test added (which is part of the examples on Elastica.io)
JSON query test added
Release v0.90.7.0