encode utf-8 characters properly before writing to csv

[pokab]

My log lines contained non-ascii characters and newlines, which ES returned as (unicode) escape sequences. These need to be encoded. Fix taken from http://stackoverflow.com/questions/5838605/python-dictwriter-writing-utf-8-encoded-csv-files

[taraslayshchuk]

Nice, but this solution breaks another thing:

AttributeError: 'int' object has no attribute 'encode'

Can you fix it, please?

[pokab]

Now it also works with a map which contains non-strings.

[taraslayshchuk]

Can you, please, merge this commits in one?

[taraslayshchuk]

Good job! Thank you!