Fix of #41
 * Query group is stored on OutputPool
   * on de-registration of queries, group-queryset map should be modified
   * add OutputPool#remove to do it
 * Fix to call @output_pool.remove() on query de-registration
 * Add tests
fix to set encoding of input String values as UTF-8
fix to do type_convert recursively, to set encodings of nested String values
v1.0.2
fixed type_convert. (Hash to Hash, Array to Array)
Merge pull request #42 from ixixi/hotfix/type_convert

fixed type_convert. (Hash to Hash, Array to Array)
move listener to outside of engine for tests
add tests for engines, temporally.
Fix bug to return [] for nil input, and add specs
v1.0.3
Update summary/description without a word "CEP".