Minor - Added XMLDoc comments to CryptoHashAlgorithm.cs
Fixed FileDownloaderUnitTests: Updated download URL to point to valid resource (old URL 404'd since repo was restructured)
Fixed Hasher: Updated CryptoHashAlgorithm API calls to match changes made in commit bca5d0abe3
Refactored TempFileRegistrar and made public methods thread safe.
Minor/ignore - Added MD and SHA acronyms to DotSettings file
Moved FileUtils and TempFileRegistrar into DotNetUtils.FS namespace and created separate file for ITempFileRegistrar
Minor/ignore - Optimized `using`s in many .cs files
Minor/ignore - Added XMLDoc comment to FileDownloadProgress.State field
Minor/ignore - Added XMLDoc comments to AssemblyUtils
Minor/ignore - Renamed variables in AssemblyUtils.GetLinkerTimestamp()
Reformatted and refactored AssemblyUtils.cs
Minor/ignore - Reformatted IWndProcObservable.cs
Refactored/reformatted DragUtils and moved ExternalDragProvider out into its own file
Refactored methods to accept a variable number of arguments in TempFileRegistrar
Minor/ignore - Moved field
Pass list of input M2TS files to FFmpeg as a temporary text file rather than directly in the CLI args

Avoids the 8191 character limit imposed by cmd.exe in Windows XP and newer.
See https://its.ffmpeg.org/wiki/How%20to%20concatenate%20(join,%20merge)%20media%20files#samecodec and http://support.microsoft.com/kb/830473
Use Guid class instead of String to represent IPlugin GUIDs
CryptoHashAlgorithm.UpperCase now defaults to `false` (previously defaulted to `true`)