* AudioService.cs: Remove metadata like the audio cover

* ProxyService.cs:
* StorageService.cs:
* GoogleAuthenticationService.cs:
* FacebookAuthenticationService.cs: Remove System.Net.WebRequest
  dependency. Use Erasme.Http.WebRequest

* ManageService.cs: Add X-Forwarded-For field

* QueueService.cs:
* VideoService.cs:
* MimeIconService.cs:
* WebshotService.cs: Cleanup

* PdfService.cs: Add support for StarOffice document

* ImageVideoPreview.cs: Add support for audio file preview using the
  cover image if present

* PdfPreview.cs: Correct a bug in PDF preview when the document has
  less than 10 pages or more than 99

* PreviewService.cs: Add support for audio file preview

* TextPreview.cs: Improve simple text preview with a bigger font size

* StaticFilesService.cs: Add bytes ranges support for static files
  service

* Erasme.Cloud.csproj:
* TestCloudClient.csproj:
* TestCloudServer.csproj: Use local libraries

* Main.cs: Add HTTP proxy test service

* changelog: Update