Add proc get type , tokenizer_list command and normalizer_list command

Add get a grn_proc_type API.
Add tokenizer_list command and normalizer_list command.
Add doc for tokenizer_list command and normalizer_list command.

Sorry, I couldn't translate the document yet...

refs [[groonga-dev,02321]](http://sourceforge.jp/projects/groonga/lists/archive/dev/2014-May/002323.html)