Fix encoding issues.

The original implementation used str.encode() on input and str.decode() on
output. However this would cause UnicodeDecodeError since certain characters
can't be encoded / decoded in ASCII.

The new solution is to use unicode() on all input strings and output UTF-8
encoded strings. This makes the assumption that the shell can handle UTF-8
strings.

Makefile

@@ -39,4 +39,5 @@ tar:
 	sha1sum autojump_v$(VERSION).tar.gz
 
 test:
-	testify -v tests
+	@find . -type f -iname "*.pyc" -delete
+	testify -v tests -x disabled