configure groonga-httpd: support BSD sed
Fix a build error on *BSD

*BSD doesn't define off64_t. We should use off_t on the environment.

GitHub: fix #253

Reported by Hiroshi Hatake. Thanks!!!
Fix a build error on OS X

GitHub: fix #254

Reported by Hiroshi Hatake. Thanks!!!
rpm centos: remove "experimental" description
doc install: introduce groonga-token-filter-stem package
Merge pull request #259 from myokoym/doc-install-token-filter-stem

doc install: introduce groonga-token-filter-stem package

Patch by Masafumi Yokoyama. Thanks!!!
deb: add missing copyright about onigmo
Fix a regression bug that "equal" against nonexitent reference always matches

grn_obj_get_value() returns value its type is not real value type
for nonexistent reference in the middle of accessor.

For example: Think about the following schema:

    table_create Bookmarks TABLE_HASH_KEY ShortText
    column_create Bookmarks title COLUMN_SCALAR ShortText

    table_create Users TABLE_HASH_KEY ShortText
    column_create Users bookmark COLUMN_SCALAR Bookmarks

And the following data:

    load --table Bookmarks
    [
    {"_key": "http://groonga.org/", "title": "Groonga"}
    ]

    load --table Users
    [
    {"_key": "alice", "bookmark": "http://groonga.org/"},
    {"_key": "bob"}
    ]

"bob" user is important. "bob"'s bookmark column value is
nonexistent. grn_obj_get_value() for "bookmark.name" accessor and "bob"
user returns Bookmarks type value not ShortText type value. Because
grn_obj_get_value() for accessor stops value resolving when there is
nonexistent reference.

With this change, grn_obj_get_value() always returns real value type
even if there is nonexistent reference.
Add a missing space between type name and "*"
Support "make install" without "make"

Reported by akira yamada. Thanks!!!
Add request cancel feature (experimental)

You can cancel a request by this feature with the following steps:

  1. Add "request_id" parameter to your request. For example:

     * "select Table --query 'body:@keyword' --request_id ID"
     * "/d/select?table=Table&query=body:@keyword&request_id=ID"

     Note that the "request_id" value should be unique in concurrent
     requests.

  2. Call "request_cancel" command with the request ID. For example:

     * "request_cancel ID"
     * "/d/request_cancel?id=ID"

  3. "request_cancel" returns the following body:

         {
           "id": "ID",
           "canceled": true
         }

      * Note that the request ID doesn't exist, "canceled" value is false.
      * You can call "request_cancel" multiple times with the same
        request ID.

  4. Request that is specified by the request ID will be canceled. The
     response has -5 (GRN_INTERRUPTED_FUNCTION_CALL) as status code.

TODO:

  * Document me.
  * Test me.
doc ja: remove a needless preceding new line
Update files
Consider the case when some of split chunks become empty.
Update mruby

    % make -C vendor/mruby update
request-canceler: just set ctx->rc for canceling

Error message and logging are done at unregistering the request.
test: add a test for 'vector @ "element"'
deb: add missing copyright
admin: fix wrong file path
Remove needless warning

We accept C99 source. For example, mruby source.