Prepare release v0.19.0.0

prepare release v0.18.6.0

Prepare release v0.18.5.0

Release v0.18.4.1 added

Merge pull request ruflin#105 from fabian/travis

Adding support for Travis

small bug fixed for ES 0.18.1

Changes updated. Type in filtertest fixed

ugly typo in Elastica_Type_Abstract::converDate fixed

source typo fixed in elastica_type

Preparing release v0.17.6.1