Add space to keep token filters key tables
Support saving IDs of token filters into spec
Support getting/setting token filters by API
Fix a typo

    grn_obj_set_info_source
    grn_obj_set_info_token_filters
                     ^^^^^^^^^^^^^
Support getting token filters
Support applying token filters
Follow API change
Export grn_token_mode
Add token filter plugin API
table_create: add --token_filters option
Add missing source to source list
Add stop-word token filter
Ignore query that all tokens are skipped

Is it a good approach?
Add missing add_library
Merge pull request #209 from groonga/support-token-filters

Support token filters