Refactoring all Strings in python2 to unicode

[Reimar Bauer]

In Python 2 we have to prefix strings by u'string' to have unicode encoding.

As long we have only english we have likly because of ASCII no conflict but we are not consistant.

[Reimar Bauer]

Fixed all format statements with potential user input to unicode.

Also enhanced some outputs, cleaned up minor stuff related to exceptions and MessageBoxes, and replaced "%" formatting of strings outside logging statements to the "format" syntax.

See Issue #126

→ <<cset ff10666d7582>>

[Reimar Bauer]

we learned during the py3 refactoring that we want to use basestring

[Reimar Bauer]

was done during the py3 refactoring