Revert "modified JestResult.getSourceAs... methods to getHits methods and added Hit class - #106"

This reverts commit b85aaaa2bae6792ba818dbd130c6c9aa1cf8aa75.
Revert "add explain support for search hits"

This reverts commit c92c1b403d7b696924a7820db3ad72877810ec88.
moved result creation logic from client to action
moved abstract action classes to new io.searchbox.action package.
parametrized abstract action classes to create different JestResult implementations.
added first parametrized action implementation Search which returns SearchResult when executed.
#106