wikipedia geocoordinates

Add ability to get coordinates for specific page and also perform
search for pages with geo coordinates
Add ability to search by title
Add ability to search by title
Fix typo
Add page coordinates and search_loc unit tests
Added link to mediawiki geo data in search_loc method.
clean up geo testing to use Decimals
clean up search_loc & tests to use Decimals
rename search_loc->geosearch and article_name->title for consistency with Mediawiki API terminology
update CHANGELOG and docs to reflect contributions
Merge branch 'master' of https://github.com/goldsmith/Wikipedia