Fix unicode argument processing for py2

In python2, sys.argv is a bytestring of whatever encoding
is used by the terminal.  In python3, sys.argv is a list of unicode
strings.  This causes problems because the rest of the code assumes
unicode.

The fix is to automatically decode to unicode based on sys.stdin
as soon as we parse the args.

This was originally reported in #593, and
https://github.com/boto/botocore/pull/218.

I'll need to more investigation to see if this problem applies
to JSON files via file://, this commit only fixes the case where
unicode is specified on the command line.
Fix case where encoding is None

This happens in our unittest.
Fix bug in test where sys.stdin is None
Update CHANGELOG with unicode fix
Remove region check in s3 high level commands

Fixes #681.
Merge branch 's3-no-region' into develop

* s3-no-region:
  Remove region check in s3 high level commands
Merge branch 'unicode-args' into develop

* unicode-args:
  Update CHANGELOG with unicode fix
  Fix bug in test where sys.stdin is None
  Fix case where encoding is None
  Fix unicode argument processing for py2
Update CHANGELOG with issue 681
Update changelog with create-snapshots issue
Fix integ test failure on windows
Quote the filename in the x-amz-copy-source header for multipart COPY operations.  Fixes #614.
Let botocore handle the quoting of the x-amz-copy-source header.
The fake session should no longer unquote the copy_source.
Don't encode the copy_source argument

Picks up on where #615 left off.
Update CHANGELOG
Fix pagination with string params
More useful error and added tests
Add Route53 max items test case
Update bundled installer to work with pip 1.5

Also added a check that we have the minimum required
versions of pip/virtualenv before creating a bundled
installer.

Verified I could create/install a bundled installer
with these changes and pip 1.5.4.

If you have the wrong version installed, you'll get:

ValueError: pip requires at least version 1.5.0, but version 1.4.1 was found.

Fixes #691.
Add 691 to changelog