Modified countrycode_data.csv regular expressions.

Needed to work in Python as well as R.  Some changes also apprent result of changes in sorting of country names.
Rewrote countrycode to better match R version.

This version works much better than my last attempt.  It mirrors the R version closely, to make it easier to maintain.  It also returns NaN for countries that could not be matched and warns in the case of non-matches or double matches.
Changes in countrycode.py.
Slight changes to countrycode.py to
1) deal with utf-8 country names properly (assumes that data table is utf-8)
2) match country names if regex matches any part, not just the beginning
3) warn if countries were not found or regex matches > 1 country
changes to regex in countrycode_data.csv.

Modified some regexes to have a wildcard at the front of the pattern.
Mostly unnecessary now because last commit on countrycode.py allows
patterns to be matched anywhere in the string, not just at the start.