Solve issues relates do character encoding

Created by: axmachado

Solve issues #286 (closed), #239 (closed) and #153 (closed).

The approach here is to use unicode string all the way, and encode it to the system default encoding only when writing to console or file. It changes a bit how things are done in "stuff.py" and "reports.py", formatting all strings in unicode before encoding to the system charset.

I removed some hardcoded "utf-8" encodings, converting it to Unicode strings.

For me, it solved all the encoding issues that where making hamster unusable in my system. I hope it work for you all too.

There is some risk of this patch breaking something related to bug 562298 (encoding issue with Japanese locale). I think it will not break, but I was unable to test it. If someone that uses Japanese locale can test, I will be glad.

I can spare some more hours to work with hamster, so, if anyone thinks any bug is really annoying, please, let me know.