index attributes with text providing source models with value _and_ label
add config value for logging
enable searching for text and value of source attributes
add the option to search products via category name
restore "search on options" config behavior
add missing bracket
apply analyzers also to attribute values
revert advance analyzing of attributes
add min score
fix index preparation

The index preparation tried to update the settings of a existing
index. But that led to to an error because the index as to be closed
before updating "non dynamic" settings like analyzers and filters.
So for now reconfiguration of existing index is disabled.
Merge branch 'develop' into feature/advanced_attribute_search
Merge branch 'develop' into feature/advanced_attribute_search
remove hard added elastica dependency
add elastica 1.3 as dependency
fix index preparation

The index preparation tried to update the settings of a existing
index. But that led to to an error because the index as to be closed
before updating "non dynamic" settings like analyzers and filters.
So for now reconfiguration of existing index is disabled.
Merge branch 'feature/elastica_1.3' into feature/advanced_attribute_search_1.3
update readme
Merge branch 'feature/advanced_attribute_search_1.3' into develop