Fix this use case: load->vars->('foobar', '')

Previously, only the other syntax was working: load->vars->(array('foobar' => ''))
Remove trailing delimiters from csv_from_result

When using the csv_from_result function, the returned string includes an
extra delimiter at the end of every line, usually a comma unless another
delimiter is specified.  A simple addition of a couple of lines to
remove the extra delimiter from the column names and the data rows is
included. (Lines 241 and 251)
added spaces after the parameter separators
Text helper: convert_accented_characters() optimization

Thanks to static variables, array_keys() and array_values() are now executed once only.
Merge pull request #2294 from vlakoff/develop-2

Text helper: convert_accented_characters() optimization
Merge pull request #2290 from jonesmdj/develop

Remove trailing delimiters from csv_from_result
Optimize changes from PR #2290
Merge pull request #2287 from vlakoff/develop

Fix this use case: load->vars->('foobar', '')
Fix Session cookie driver storing untrimmed user agent string in the database causing set_userdata() calls to fail when $config['sess_match_useragent'] = TRUE