Add support for retaining executable bit on files

[Zygmunt Krynicki]

Ubuntu One supports Linux, Windows and it is reasonable to assume, will support Mac OSX as well.

We should not force all our users to loose the executable bit on their files, especially when competing products (such as DropBox) support this feature.

I'd like to prpose that this feature be implemented in ubuntuone.

On windows:
 * the executable bit is remembered but not visible in the filesystem
 * it is not lost on renames

On mac and linux:
 * the executable bit is synchronized and applied normally

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: ubuntuone-client 3.99.91-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-14.16-generic 3.5.3
Uname: Linux 3.5.0-14-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.5.1-0ubuntu7
Architecture: amd64
Date: Thu Sep 13 13:40:22 2012
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120905.2)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntuone-client
UpgradeStatus: No upgrade log present (probably fresh install)

[Leo Arias (elopio)]

Currently Ubuntu One does not sync metadata about files (last modified time, permissions). The biggest problem is that different systems store different metadata and those that do store similar metadata store it in different ways. There is a bug report you can comment on here: https://bugs.launchpad.net/ubuntuone-client/+bug/385511