Bug fix for resume download, and some improvements

[ksmith3036]

Bug fixes

• Fixed resume of download, when downloaded file has passed 2 GByte in size. Workaround for .NET HttpClient bug for Range header.

Changes

• Switched to newAuth=1 => removed dependency to AgentModule.dll, CommonModule.dll and GlobalUtil.dll
• Switched to build for AnyCpu (since no need for 32-bit Samsung dll's)
• Builds with Visual Studio 2019 and .NET Framework 4.7.2
• Changed phone model and region to ComboBoxes, to have dropdown lists of previous downloaded firmwares.
• Downloaded models and regions stored to SamFirm.xml, to populate combo boxes.
• Auto unzipping while decrypting downloaded firmware file.
• Saving metadata file FirmwareInfo.txt to folder for unzipped firmware files.

[ivanmeler]

This is amazing, ive been planing to do something similar for some time but never found enough. Ill test this for a while and merge it after testing, and of course add you to credits as you really deserve it for this