Overall cleanup (grammar, misspellings) of README in English for joker-x...

Another pass on the English translation for #2 to take care of some minor grammar and spelling mistakes. The included example was also updated to rely on the loading of the CSV file before creating the GeoCSV layer itself.

The only other spelling error I see is `deleteDobleQuotes` should be `deleteDoubleQuotes`; but that would introduce an API error unless the "doble" version was aliased so I wanted to ask for thoughts first.