[BUG] Unicode string must be always used with encodings

[Alexander Belchenko]

I suppose that:

* for control files it must be used utf-8 always,
* for input from user it must be used input_encoding (sys.stdin.encoding 
or user_encoding),
* for output to user it must be used output_encoding 
(sys.stdout.encoding or user_encoding)
* for decode filenames to unicode strings it must be used user_encoding

If my assumption is right, then I will be able to start implement these.

Also I think it will be good to have global options for pointing to bzr 
default encoding for input/output, like docutils do:

--input-encoding=XXX or -iXXX  		-- for input encoding
--output-encoding=XXX or -oXXX 		-- for output encoding

Is this global options free in bzr design?

Alexander.