Add smart method of matching

[Zeno Dalla Valle]

It would be nice to implement a method that lets you link your data with geospatial and population data based on more sophisticated matching techniques.
For example it could be enough to recognize a province name inside a text to match that text to the province.
Furthermore it could be useful to pass to the function a match_mode argument that lets you choose what to do with matches:

• 'sure': match is ok only if one match is found in the entire text;
• 'first': at the first match match is confirmed, whatever the next words are.

An other useful parameter would be split that would be the regex pattern used to split the text into words.