If the number of connected resources is appended in parentheses,
the appropriate ltr or rtl mark is inserted before, so that the
writing direction at the end of the nickname matches the writing
direction of the whole displayed string as determined by
http://www.unicode.org/reports/tr9/#The_Paragraph_Level

don't remove a file before renaming under windows because os.remove('test') will remove 'TEST' under window. Fixes #5279

Also use % formatting instead of string replace.
Translation files updated accordingly.

when a JID is invalid in member / admin / ... list in MUC configuration, just ignore this JID and not all others. Fixes #5241

show only once unread messages at startup when we have twice the same contact in 2 accounts. Fixes #2921