Split md5/hardlink stuff out of SortedDict into FileDict

I should not have overloaded SortedDict with all the md5 and hardlink
tracking stuff which only used by file lists.  There are other uses of
SortedDict elsewhere in the app that need not be cluttered by these
additional features in SortedDict.

Solution: derive new class FileDict from SortedDict, and put the md5
and hardlink tracking code into that.  Then use FileDict instead of
SortedDict where those features are needed.
Add quiet option to silence output on stdout
Merge pull request #136 from tjasond/master

mktemp permission issue, fix
Wrap quiet option in try/except
Merge pull request #135 from sidprak/add-quiet-option

Add --quiet option to silence output on stdout
Changed error message for --quiet
Merge pull request #134 from mdomsch/cleanup/filedict

Split md5/hardlink stuff out of SortedDict into FileDict
fix sync single remote file to existing local file traceback, bug 88

fixes https://github.com/s3tools/s3cmd/issues/88

We were getting a traceback:

remote_list[remote_list.keys()[0]]['local_filename'] = deunicodise(destination_base)
IndexError: list index out of range

In this instance, remote_list length is 0 because the file is on the
update_list instead.  We'll get to process that in a bit.  The right
thing to do in _set_local_filename() is to simply return if the list
length is zero - there's nothing for us to do.
Reverted e86de36 - Reuse a single connection when doing a bucket list

We need a more generic approach to connection pooling.
Reuse HTTP connections

Revived very old approach from v0.9.9-speedup branch (149226b)
TODO: Proxies not supported!
Add proxy support
Merge branch 'http-speedup'
Merge branch 'master' of ssh://github.com/s3tools/s3cmd
Version 1.5.0-alpha3
Merge pull request #137 from mdomsch/bug/88

fix sync single remote file to existing local file traceback, bug 88
Add missing import of errno in S3.py
Merge pull request #140 from bobbyi/missing_import

Add missing import of errno in S3.py
IAM role typo fixes
Merge pull request #145 from dudyk/IAM-fixes

IAM role typo fixes
Windows fix re / vs os.path.sep

Even on Windows where os.path.sep is backslash, forward-slash is the S3 separator character.