Add get a grn_proc_type API

New functions:
  * grn_proc_get_type()
Add tokenizer_list command and normalizer_list command
doc:add tokenizer list command and normalizer_list command

TODO:
Translate it in doc/locale/ja/LC_MESSAGES/reference.po
Translate it in doc/locale/en/LC_MESSAGES/reference.po
Merge pull request #171 from naoa/add-proc-get-type

Add proc get type , tokenizer_list command and normalizer_list command

Patch by Naoya Murakami. Thanks!!!