add method to convert currency value to text
get_object supports backend's services returning lists
in interactive mode, 'transfer' commands asks confirmation (refs #1077)
remove useless import of with_statement (we do not support anymore python2.5)

refs #806
Remove some from __future__, forbid 2.5 in setup
Use newer form of catching exceptions

autopep8 -i --select=W602
Also some other minor deprecated syntax changes, like "while 1".
I did not commit the less obvious changes.
pyflakes.sh: Ban more stuff
No need to support deprecated cgi module
Use NamedTemporaryFile(delete=False) instead of mkstemp