Implement query location method to search for place names

[cbiehl]

This implements the Nominatim.query_location method for searching for place names with a simple string contains search and (if users install the thefuzz package) a fuzzy string search based on edit distance. Please let me know if you need any changes or unit tests to consider a merge.

Closes https://github.com/symerio/pgeocode/issues/29

[cbiehl]

@rth Ping

[rth]

Also let's add,

    extras_require={
        "fuzzy": ["thefuzz"],
    },

to setup.py to make it an optional dependency, and,

• it would be good to add an example of using this to the readme https://github.com/symerio/pgeocode#quickstart
• please add a changelog entry under the "[unreleased]" version on the top.

[cbiehl]

Thanks for the review! I'll push an update later this week.

[rth]

Thanks a lot @cbiehl !