libvoikko: API + voikkospell options for displaying dictionary paths

[hatapitk]

From Sjur at libvoikko mailing list:

It would be even better if the command line tools could be enhanced with an option to query this value, e.g. something like:

$ voikkospell --dict-path /the/path:/that/was/specified

And --verbose + -l would list the dictionary files with their full path:

$ voikkospell -l --verbose smn-x-standard (/path/to/dict.file): Giellatekno/Divvun/UiT fst-based speller for Inari Sami

or something like that.

This way it is possible both to always get a full list of directories searched, and it will also help developers/linguists in cases of dictionary conflicts (several dictionaries for the same language - a surprisingly common error source:)